357450
If we add impurity to a metal those atoms also deflect electrons. Therefore,
1 the electrical and thermal conductivities both increase.
2 the electrical and thermal conductivities both decrease.
3 the electrical conductivity increases but thermal conductivity decreases.
4 the electrical conductivity decreases but thermal conductivity increases.
Explanation:
The electrons increase their number of collisions increasing the thermal and electrical resistance. Hence the electrical and thermal conductivities both decrease.
PHXII03:CURRENT ELECTRICITY
357451
Assertion : Electrical appliances with metallic body; e.g. heaters, presses etc, have three pin connections, whereas an electric bulb has a two pin connection. Reason : Three pin connection increases heating of connecting cables.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Electric appliances with metallic bodies like heaters and presses often have three-pin connections for safety purposes. The third pin, known as the Earth or Ground pin, is meant to provide an additional path for electrical current to safely dissipate into the ground in the event of a fault or short circuit, preventing electrical shocks or fires. It reduces heating of connecting cables, and contributes to overall electrical safety. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357452
Assertion : A bird perches on a high power line and nothing happens to the bird. Reason : The level of bird is very high from the ground.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Birds perching on high-power lines are safe as there's no potential difference between them and the line i.e,. bird is on equipotential surface. preventing current flow. In contrast, humans can experience electric shock if they create a potential difference by touching the power line and the ground simultaneously as hands are at high potential. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357453
Assertion : A laser beam \(0.2\;W\) power can drill holes through a metal sheet, whereas \(100\;W\) torch-light cannot. Reason : The frequency of laser light is much higher than that of torch light.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Laser is highly intense beam compared to usual bulbs. Drilling hole on metal sheet involves small area. \(\Rightarrow\) Laser can drill such holes. Light beam from 'Torch light' is not intense nor perfectly parallel so as to focus. But frequency of laser just indicates energy. LASER also can be in visible range as usual light of bulb is. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357454
By what percentage will the illumination of the lamp decrease if the current drops by \(20 \%\) ?
1 \(56 \%\)
2 \(46 \%\)
3 \(26 \%\)
4 \(36 \%\)
Explanation:
\(H=I^{2} R t \Rightarrow H \propto i^{2}\) \(\Rightarrow \dfrac{H_{2}}{H_{1}}=\left(\dfrac{i_{2}}{i_{1}}\right)^{2}\) \(i_{2}=i_{1}-\dfrac{20}{100} i_{1}=\dfrac{80 i_{1}}{100}=\dfrac{4 i_{1}}{5}\) \(\dfrac{H_{2}}{H_{1}}=\left(\dfrac{\dfrac{4}{5} i_{1}}{i_{1}}\right)^{2}=\dfrac{16}{25}\) The percentage decrease in illumination is given by \(\frac{{{H_1} - {H_2}}}{{{H_1}}} \times 100\,\% = \left( {1 - \frac{{{H_2}}}{{{H_1}}}} \right) \times 100\,\% \) \( = \left( {1 - \frac{{16}}{{25}}} \right) \times 100\,\% \) \( = 36\,\% \)
357450
If we add impurity to a metal those atoms also deflect electrons. Therefore,
1 the electrical and thermal conductivities both increase.
2 the electrical and thermal conductivities both decrease.
3 the electrical conductivity increases but thermal conductivity decreases.
4 the electrical conductivity decreases but thermal conductivity increases.
Explanation:
The electrons increase their number of collisions increasing the thermal and electrical resistance. Hence the electrical and thermal conductivities both decrease.
PHXII03:CURRENT ELECTRICITY
357451
Assertion : Electrical appliances with metallic body; e.g. heaters, presses etc, have three pin connections, whereas an electric bulb has a two pin connection. Reason : Three pin connection increases heating of connecting cables.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Electric appliances with metallic bodies like heaters and presses often have three-pin connections for safety purposes. The third pin, known as the Earth or Ground pin, is meant to provide an additional path for electrical current to safely dissipate into the ground in the event of a fault or short circuit, preventing electrical shocks or fires. It reduces heating of connecting cables, and contributes to overall electrical safety. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357452
Assertion : A bird perches on a high power line and nothing happens to the bird. Reason : The level of bird is very high from the ground.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Birds perching on high-power lines are safe as there's no potential difference between them and the line i.e,. bird is on equipotential surface. preventing current flow. In contrast, humans can experience electric shock if they create a potential difference by touching the power line and the ground simultaneously as hands are at high potential. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357453
Assertion : A laser beam \(0.2\;W\) power can drill holes through a metal sheet, whereas \(100\;W\) torch-light cannot. Reason : The frequency of laser light is much higher than that of torch light.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Laser is highly intense beam compared to usual bulbs. Drilling hole on metal sheet involves small area. \(\Rightarrow\) Laser can drill such holes. Light beam from 'Torch light' is not intense nor perfectly parallel so as to focus. But frequency of laser just indicates energy. LASER also can be in visible range as usual light of bulb is. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357454
By what percentage will the illumination of the lamp decrease if the current drops by \(20 \%\) ?
1 \(56 \%\)
2 \(46 \%\)
3 \(26 \%\)
4 \(36 \%\)
Explanation:
\(H=I^{2} R t \Rightarrow H \propto i^{2}\) \(\Rightarrow \dfrac{H_{2}}{H_{1}}=\left(\dfrac{i_{2}}{i_{1}}\right)^{2}\) \(i_{2}=i_{1}-\dfrac{20}{100} i_{1}=\dfrac{80 i_{1}}{100}=\dfrac{4 i_{1}}{5}\) \(\dfrac{H_{2}}{H_{1}}=\left(\dfrac{\dfrac{4}{5} i_{1}}{i_{1}}\right)^{2}=\dfrac{16}{25}\) The percentage decrease in illumination is given by \(\frac{{{H_1} - {H_2}}}{{{H_1}}} \times 100\,\% = \left( {1 - \frac{{{H_2}}}{{{H_1}}}} \right) \times 100\,\% \) \( = \left( {1 - \frac{{16}}{{25}}} \right) \times 100\,\% \) \( = 36\,\% \)
357450
If we add impurity to a metal those atoms also deflect electrons. Therefore,
1 the electrical and thermal conductivities both increase.
2 the electrical and thermal conductivities both decrease.
3 the electrical conductivity increases but thermal conductivity decreases.
4 the electrical conductivity decreases but thermal conductivity increases.
Explanation:
The electrons increase their number of collisions increasing the thermal and electrical resistance. Hence the electrical and thermal conductivities both decrease.
PHXII03:CURRENT ELECTRICITY
357451
Assertion : Electrical appliances with metallic body; e.g. heaters, presses etc, have three pin connections, whereas an electric bulb has a two pin connection. Reason : Three pin connection increases heating of connecting cables.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Electric appliances with metallic bodies like heaters and presses often have three-pin connections for safety purposes. The third pin, known as the Earth or Ground pin, is meant to provide an additional path for electrical current to safely dissipate into the ground in the event of a fault or short circuit, preventing electrical shocks or fires. It reduces heating of connecting cables, and contributes to overall electrical safety. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357452
Assertion : A bird perches on a high power line and nothing happens to the bird. Reason : The level of bird is very high from the ground.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Birds perching on high-power lines are safe as there's no potential difference between them and the line i.e,. bird is on equipotential surface. preventing current flow. In contrast, humans can experience electric shock if they create a potential difference by touching the power line and the ground simultaneously as hands are at high potential. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357453
Assertion : A laser beam \(0.2\;W\) power can drill holes through a metal sheet, whereas \(100\;W\) torch-light cannot. Reason : The frequency of laser light is much higher than that of torch light.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Laser is highly intense beam compared to usual bulbs. Drilling hole on metal sheet involves small area. \(\Rightarrow\) Laser can drill such holes. Light beam from 'Torch light' is not intense nor perfectly parallel so as to focus. But frequency of laser just indicates energy. LASER also can be in visible range as usual light of bulb is. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357454
By what percentage will the illumination of the lamp decrease if the current drops by \(20 \%\) ?
1 \(56 \%\)
2 \(46 \%\)
3 \(26 \%\)
4 \(36 \%\)
Explanation:
\(H=I^{2} R t \Rightarrow H \propto i^{2}\) \(\Rightarrow \dfrac{H_{2}}{H_{1}}=\left(\dfrac{i_{2}}{i_{1}}\right)^{2}\) \(i_{2}=i_{1}-\dfrac{20}{100} i_{1}=\dfrac{80 i_{1}}{100}=\dfrac{4 i_{1}}{5}\) \(\dfrac{H_{2}}{H_{1}}=\left(\dfrac{\dfrac{4}{5} i_{1}}{i_{1}}\right)^{2}=\dfrac{16}{25}\) The percentage decrease in illumination is given by \(\frac{{{H_1} - {H_2}}}{{{H_1}}} \times 100\,\% = \left( {1 - \frac{{{H_2}}}{{{H_1}}}} \right) \times 100\,\% \) \( = \left( {1 - \frac{{16}}{{25}}} \right) \times 100\,\% \) \( = 36\,\% \)
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PHXII03:CURRENT ELECTRICITY
357450
If we add impurity to a metal those atoms also deflect electrons. Therefore,
1 the electrical and thermal conductivities both increase.
2 the electrical and thermal conductivities both decrease.
3 the electrical conductivity increases but thermal conductivity decreases.
4 the electrical conductivity decreases but thermal conductivity increases.
Explanation:
The electrons increase their number of collisions increasing the thermal and electrical resistance. Hence the electrical and thermal conductivities both decrease.
PHXII03:CURRENT ELECTRICITY
357451
Assertion : Electrical appliances with metallic body; e.g. heaters, presses etc, have three pin connections, whereas an electric bulb has a two pin connection. Reason : Three pin connection increases heating of connecting cables.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Electric appliances with metallic bodies like heaters and presses often have three-pin connections for safety purposes. The third pin, known as the Earth or Ground pin, is meant to provide an additional path for electrical current to safely dissipate into the ground in the event of a fault or short circuit, preventing electrical shocks or fires. It reduces heating of connecting cables, and contributes to overall electrical safety. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357452
Assertion : A bird perches on a high power line and nothing happens to the bird. Reason : The level of bird is very high from the ground.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Birds perching on high-power lines are safe as there's no potential difference between them and the line i.e,. bird is on equipotential surface. preventing current flow. In contrast, humans can experience electric shock if they create a potential difference by touching the power line and the ground simultaneously as hands are at high potential. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357453
Assertion : A laser beam \(0.2\;W\) power can drill holes through a metal sheet, whereas \(100\;W\) torch-light cannot. Reason : The frequency of laser light is much higher than that of torch light.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Laser is highly intense beam compared to usual bulbs. Drilling hole on metal sheet involves small area. \(\Rightarrow\) Laser can drill such holes. Light beam from 'Torch light' is not intense nor perfectly parallel so as to focus. But frequency of laser just indicates energy. LASER also can be in visible range as usual light of bulb is. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357454
By what percentage will the illumination of the lamp decrease if the current drops by \(20 \%\) ?
1 \(56 \%\)
2 \(46 \%\)
3 \(26 \%\)
4 \(36 \%\)
Explanation:
\(H=I^{2} R t \Rightarrow H \propto i^{2}\) \(\Rightarrow \dfrac{H_{2}}{H_{1}}=\left(\dfrac{i_{2}}{i_{1}}\right)^{2}\) \(i_{2}=i_{1}-\dfrac{20}{100} i_{1}=\dfrac{80 i_{1}}{100}=\dfrac{4 i_{1}}{5}\) \(\dfrac{H_{2}}{H_{1}}=\left(\dfrac{\dfrac{4}{5} i_{1}}{i_{1}}\right)^{2}=\dfrac{16}{25}\) The percentage decrease in illumination is given by \(\frac{{{H_1} - {H_2}}}{{{H_1}}} \times 100\,\% = \left( {1 - \frac{{{H_2}}}{{{H_1}}}} \right) \times 100\,\% \) \( = \left( {1 - \frac{{16}}{{25}}} \right) \times 100\,\% \) \( = 36\,\% \)
357450
If we add impurity to a metal those atoms also deflect electrons. Therefore,
1 the electrical and thermal conductivities both increase.
2 the electrical and thermal conductivities both decrease.
3 the electrical conductivity increases but thermal conductivity decreases.
4 the electrical conductivity decreases but thermal conductivity increases.
Explanation:
The electrons increase their number of collisions increasing the thermal and electrical resistance. Hence the electrical and thermal conductivities both decrease.
PHXII03:CURRENT ELECTRICITY
357451
Assertion : Electrical appliances with metallic body; e.g. heaters, presses etc, have three pin connections, whereas an electric bulb has a two pin connection. Reason : Three pin connection increases heating of connecting cables.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Electric appliances with metallic bodies like heaters and presses often have three-pin connections for safety purposes. The third pin, known as the Earth or Ground pin, is meant to provide an additional path for electrical current to safely dissipate into the ground in the event of a fault or short circuit, preventing electrical shocks or fires. It reduces heating of connecting cables, and contributes to overall electrical safety. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357452
Assertion : A bird perches on a high power line and nothing happens to the bird. Reason : The level of bird is very high from the ground.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Birds perching on high-power lines are safe as there's no potential difference between them and the line i.e,. bird is on equipotential surface. preventing current flow. In contrast, humans can experience electric shock if they create a potential difference by touching the power line and the ground simultaneously as hands are at high potential. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357453
Assertion : A laser beam \(0.2\;W\) power can drill holes through a metal sheet, whereas \(100\;W\) torch-light cannot. Reason : The frequency of laser light is much higher than that of torch light.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Laser is highly intense beam compared to usual bulbs. Drilling hole on metal sheet involves small area. \(\Rightarrow\) Laser can drill such holes. Light beam from 'Torch light' is not intense nor perfectly parallel so as to focus. But frequency of laser just indicates energy. LASER also can be in visible range as usual light of bulb is. So correct option is (3).
PHXII03:CURRENT ELECTRICITY
357454
By what percentage will the illumination of the lamp decrease if the current drops by \(20 \%\) ?
1 \(56 \%\)
2 \(46 \%\)
3 \(26 \%\)
4 \(36 \%\)
Explanation:
\(H=I^{2} R t \Rightarrow H \propto i^{2}\) \(\Rightarrow \dfrac{H_{2}}{H_{1}}=\left(\dfrac{i_{2}}{i_{1}}\right)^{2}\) \(i_{2}=i_{1}-\dfrac{20}{100} i_{1}=\dfrac{80 i_{1}}{100}=\dfrac{4 i_{1}}{5}\) \(\dfrac{H_{2}}{H_{1}}=\left(\dfrac{\dfrac{4}{5} i_{1}}{i_{1}}\right)^{2}=\dfrac{16}{25}\) The percentage decrease in illumination is given by \(\frac{{{H_1} - {H_2}}}{{{H_1}}} \times 100\,\% = \left( {1 - \frac{{{H_2}}}{{{H_1}}}} \right) \times 100\,\% \) \( = \left( {1 - \frac{{16}}{{25}}} \right) \times 100\,\% \) \( = 36\,\% \)