238728
Assertion: Threshold frequency is the maximum frequency required for the ejection of electron from the metal surface. Reason: Threshold frequency is characteristic of a metal.
1 If both Assertion and Reason are correct and the Reason is the correct explanation of Assertion
2 If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
3 If Assertion is correct but Reason is incorrect.
4 If both the Assertion and Reason are incorrect.
Explanation:
: Threshold frequency is a minimum frequency required for the emission of electron from the metal surface.
AIIMS-26 May
Structure of Atom
238738
The de-Broglie wavelength of a particle with mass $1 \mathrm{~g}$ and velocity $100 \mathrm{~m} / \mathrm{s}$ is
238742
In hydrogen atom, the de Broglie wavelength of an electron in the second Bohr orbit is [Given that Bohr radius, $\mathrm{a}_0=52.9 \mathrm{pm}$ ]
1 $211.6 \mathrm{pm}$
2 $211.6 \pi \mathrm{pm}$
3 $52.9 \pi \mathrm{pm}$
4 $105.8 \mathrm{pm}$
Explanation:
: According to Bohr, $\begin{aligned} & \mathrm{mvr}=\frac{\mathrm{nh}}{2 \pi} \\ & 2 \pi \mathrm{r}=\frac{\mathrm{nh}}{\mathrm{mv}}=\mathrm{n} \lambda \end{aligned}$ Where, $\mathrm{r}=$ Radius $\lambda=$ Wavelength $\mathrm{n}=$ Number of orbit Also, $r=\frac{a_0 n^2}{z}$ Where, $\mathrm{a}_{\mathrm{o}}=$ Bohr radius $=52.9 \mathrm{pm}$ $\mathrm{Z}=$ Atomic number On substituting the value of ' $r$ ' from equation (ii) to equation (i) we get $\begin{aligned} & \mathrm{n} \lambda=\frac{2 \pi \mathrm{n}^2 \mathrm{a}_{\mathrm{o}}}{\mathrm{z}} \\ & \lambda=\frac{2 \pi \mathrm{na}_{\mathrm{o}}}{\mathrm{z}} \\ & \lambda=2 \pi \times 2 \times 52.9 \quad[\because \mathrm{n}=2, \mathrm{z}=1] \\ & \lambda=211.6 \pi \mathrm{pm} \\ & \end{aligned}$
238728
Assertion: Threshold frequency is the maximum frequency required for the ejection of electron from the metal surface. Reason: Threshold frequency is characteristic of a metal.
1 If both Assertion and Reason are correct and the Reason is the correct explanation of Assertion
2 If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
3 If Assertion is correct but Reason is incorrect.
4 If both the Assertion and Reason are incorrect.
Explanation:
: Threshold frequency is a minimum frequency required for the emission of electron from the metal surface.
AIIMS-26 May
Structure of Atom
238738
The de-Broglie wavelength of a particle with mass $1 \mathrm{~g}$ and velocity $100 \mathrm{~m} / \mathrm{s}$ is
238742
In hydrogen atom, the de Broglie wavelength of an electron in the second Bohr orbit is [Given that Bohr radius, $\mathrm{a}_0=52.9 \mathrm{pm}$ ]
1 $211.6 \mathrm{pm}$
2 $211.6 \pi \mathrm{pm}$
3 $52.9 \pi \mathrm{pm}$
4 $105.8 \mathrm{pm}$
Explanation:
: According to Bohr, $\begin{aligned} & \mathrm{mvr}=\frac{\mathrm{nh}}{2 \pi} \\ & 2 \pi \mathrm{r}=\frac{\mathrm{nh}}{\mathrm{mv}}=\mathrm{n} \lambda \end{aligned}$ Where, $\mathrm{r}=$ Radius $\lambda=$ Wavelength $\mathrm{n}=$ Number of orbit Also, $r=\frac{a_0 n^2}{z}$ Where, $\mathrm{a}_{\mathrm{o}}=$ Bohr radius $=52.9 \mathrm{pm}$ $\mathrm{Z}=$ Atomic number On substituting the value of ' $r$ ' from equation (ii) to equation (i) we get $\begin{aligned} & \mathrm{n} \lambda=\frac{2 \pi \mathrm{n}^2 \mathrm{a}_{\mathrm{o}}}{\mathrm{z}} \\ & \lambda=\frac{2 \pi \mathrm{na}_{\mathrm{o}}}{\mathrm{z}} \\ & \lambda=2 \pi \times 2 \times 52.9 \quad[\because \mathrm{n}=2, \mathrm{z}=1] \\ & \lambda=211.6 \pi \mathrm{pm} \\ & \end{aligned}$
238728
Assertion: Threshold frequency is the maximum frequency required for the ejection of electron from the metal surface. Reason: Threshold frequency is characteristic of a metal.
1 If both Assertion and Reason are correct and the Reason is the correct explanation of Assertion
2 If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
3 If Assertion is correct but Reason is incorrect.
4 If both the Assertion and Reason are incorrect.
Explanation:
: Threshold frequency is a minimum frequency required for the emission of electron from the metal surface.
AIIMS-26 May
Structure of Atom
238738
The de-Broglie wavelength of a particle with mass $1 \mathrm{~g}$ and velocity $100 \mathrm{~m} / \mathrm{s}$ is
238742
In hydrogen atom, the de Broglie wavelength of an electron in the second Bohr orbit is [Given that Bohr radius, $\mathrm{a}_0=52.9 \mathrm{pm}$ ]
1 $211.6 \mathrm{pm}$
2 $211.6 \pi \mathrm{pm}$
3 $52.9 \pi \mathrm{pm}$
4 $105.8 \mathrm{pm}$
Explanation:
: According to Bohr, $\begin{aligned} & \mathrm{mvr}=\frac{\mathrm{nh}}{2 \pi} \\ & 2 \pi \mathrm{r}=\frac{\mathrm{nh}}{\mathrm{mv}}=\mathrm{n} \lambda \end{aligned}$ Where, $\mathrm{r}=$ Radius $\lambda=$ Wavelength $\mathrm{n}=$ Number of orbit Also, $r=\frac{a_0 n^2}{z}$ Where, $\mathrm{a}_{\mathrm{o}}=$ Bohr radius $=52.9 \mathrm{pm}$ $\mathrm{Z}=$ Atomic number On substituting the value of ' $r$ ' from equation (ii) to equation (i) we get $\begin{aligned} & \mathrm{n} \lambda=\frac{2 \pi \mathrm{n}^2 \mathrm{a}_{\mathrm{o}}}{\mathrm{z}} \\ & \lambda=\frac{2 \pi \mathrm{na}_{\mathrm{o}}}{\mathrm{z}} \\ & \lambda=2 \pi \times 2 \times 52.9 \quad[\because \mathrm{n}=2, \mathrm{z}=1] \\ & \lambda=211.6 \pi \mathrm{pm} \\ & \end{aligned}$
238728
Assertion: Threshold frequency is the maximum frequency required for the ejection of electron from the metal surface. Reason: Threshold frequency is characteristic of a metal.
1 If both Assertion and Reason are correct and the Reason is the correct explanation of Assertion
2 If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
3 If Assertion is correct but Reason is incorrect.
4 If both the Assertion and Reason are incorrect.
Explanation:
: Threshold frequency is a minimum frequency required for the emission of electron from the metal surface.
AIIMS-26 May
Structure of Atom
238738
The de-Broglie wavelength of a particle with mass $1 \mathrm{~g}$ and velocity $100 \mathrm{~m} / \mathrm{s}$ is
238742
In hydrogen atom, the de Broglie wavelength of an electron in the second Bohr orbit is [Given that Bohr radius, $\mathrm{a}_0=52.9 \mathrm{pm}$ ]
1 $211.6 \mathrm{pm}$
2 $211.6 \pi \mathrm{pm}$
3 $52.9 \pi \mathrm{pm}$
4 $105.8 \mathrm{pm}$
Explanation:
: According to Bohr, $\begin{aligned} & \mathrm{mvr}=\frac{\mathrm{nh}}{2 \pi} \\ & 2 \pi \mathrm{r}=\frac{\mathrm{nh}}{\mathrm{mv}}=\mathrm{n} \lambda \end{aligned}$ Where, $\mathrm{r}=$ Radius $\lambda=$ Wavelength $\mathrm{n}=$ Number of orbit Also, $r=\frac{a_0 n^2}{z}$ Where, $\mathrm{a}_{\mathrm{o}}=$ Bohr radius $=52.9 \mathrm{pm}$ $\mathrm{Z}=$ Atomic number On substituting the value of ' $r$ ' from equation (ii) to equation (i) we get $\begin{aligned} & \mathrm{n} \lambda=\frac{2 \pi \mathrm{n}^2 \mathrm{a}_{\mathrm{o}}}{\mathrm{z}} \\ & \lambda=\frac{2 \pi \mathrm{na}_{\mathrm{o}}}{\mathrm{z}} \\ & \lambda=2 \pi \times 2 \times 52.9 \quad[\because \mathrm{n}=2, \mathrm{z}=1] \\ & \lambda=211.6 \pi \mathrm{pm} \\ & \end{aligned}$
