OHM'SLAW AND COMBINATION OF RESISTANCES
Current Electricity

268474 The resistance of a platinum wire of a platinum resistance thermometer at the ice point is\(5 \Omega\) and at steam point is \(5.4 \Omega\). When the thermometer is inserted in a hot bath, the resistance of the platinum wire is \(6.2 \Omega\). Find the temperature of the hot bath.

1 \(3000^{\circ} \mathrm{C}\)
2 \(30^{\circ} \mathrm{C}\)
3 \(300^{\circ} \mathrm{C}\)
4 \(300 \mathrm{~K}\)
Current Electricity

268475 Three unequal resistors in parallel are equivalent to a resistance 1 ohm. If two of them are in the ratio\(1: 2\) and if no resistance value is fractional, the largest of the three resistance in ohm is

1 4
2 6
3 8
4 12
Current Electricity

268476 A carbon filament has resistance of\(120 \Omega\) at \(0^{\circ} \mathrm{C}\) what must be the resistance of a copper filament connected in series with carbon so that combination has same resistance at all temperatures
\(\begin{aligned}
& \left(\alpha_{\text {carton }}=-5 \times 10^{-4} /{ }^{\circ} \mathrm{C}, \alpha_{\text {copper }}=4 \times 10^{-3} /{ }^{\circ} \mathrm{C}\right) \\
& \begin{array}{llll}
\text { 1) } 120 \Omega & \text { 2) } 15 \Omega & \text { 3) } 60 \Omega & \text { 4) } 210 \Omega
\end{array}
\end{aligned}\)

1 \(120 \Omega\)
2 \(15 \Omega\)
3 \(60 \Omega\)
4 \(210 \Omega\)
Current Electricity

268477 Theequivalent resistance across \(X Y\) in fig.

1 \(r\)
2 \(2 r\)
3 \(4 r\)
4 \(r / 2\)
Current Electricity

268474 The resistance of a platinum wire of a platinum resistance thermometer at the ice point is\(5 \Omega\) and at steam point is \(5.4 \Omega\). When the thermometer is inserted in a hot bath, the resistance of the platinum wire is \(6.2 \Omega\). Find the temperature of the hot bath.

1 \(3000^{\circ} \mathrm{C}\)
2 \(30^{\circ} \mathrm{C}\)
3 \(300^{\circ} \mathrm{C}\)
4 \(300 \mathrm{~K}\)
Current Electricity

268475 Three unequal resistors in parallel are equivalent to a resistance 1 ohm. If two of them are in the ratio\(1: 2\) and if no resistance value is fractional, the largest of the three resistance in ohm is

1 4
2 6
3 8
4 12
Current Electricity

268476 A carbon filament has resistance of\(120 \Omega\) at \(0^{\circ} \mathrm{C}\) what must be the resistance of a copper filament connected in series with carbon so that combination has same resistance at all temperatures
\(\begin{aligned}
& \left(\alpha_{\text {carton }}=-5 \times 10^{-4} /{ }^{\circ} \mathrm{C}, \alpha_{\text {copper }}=4 \times 10^{-3} /{ }^{\circ} \mathrm{C}\right) \\
& \begin{array}{llll}
\text { 1) } 120 \Omega & \text { 2) } 15 \Omega & \text { 3) } 60 \Omega & \text { 4) } 210 \Omega
\end{array}
\end{aligned}\)

1 \(120 \Omega\)
2 \(15 \Omega\)
3 \(60 \Omega\)
4 \(210 \Omega\)
Current Electricity

268477 Theequivalent resistance across \(X Y\) in fig.

1 \(r\)
2 \(2 r\)
3 \(4 r\)
4 \(r / 2\)
Current Electricity

268474 The resistance of a platinum wire of a platinum resistance thermometer at the ice point is\(5 \Omega\) and at steam point is \(5.4 \Omega\). When the thermometer is inserted in a hot bath, the resistance of the platinum wire is \(6.2 \Omega\). Find the temperature of the hot bath.

1 \(3000^{\circ} \mathrm{C}\)
2 \(30^{\circ} \mathrm{C}\)
3 \(300^{\circ} \mathrm{C}\)
4 \(300 \mathrm{~K}\)
Current Electricity

268475 Three unequal resistors in parallel are equivalent to a resistance 1 ohm. If two of them are in the ratio\(1: 2\) and if no resistance value is fractional, the largest of the three resistance in ohm is

1 4
2 6
3 8
4 12
Current Electricity

268476 A carbon filament has resistance of\(120 \Omega\) at \(0^{\circ} \mathrm{C}\) what must be the resistance of a copper filament connected in series with carbon so that combination has same resistance at all temperatures
\(\begin{aligned}
& \left(\alpha_{\text {carton }}=-5 \times 10^{-4} /{ }^{\circ} \mathrm{C}, \alpha_{\text {copper }}=4 \times 10^{-3} /{ }^{\circ} \mathrm{C}\right) \\
& \begin{array}{llll}
\text { 1) } 120 \Omega & \text { 2) } 15 \Omega & \text { 3) } 60 \Omega & \text { 4) } 210 \Omega
\end{array}
\end{aligned}\)

1 \(120 \Omega\)
2 \(15 \Omega\)
3 \(60 \Omega\)
4 \(210 \Omega\)
Current Electricity

268477 Theequivalent resistance across \(X Y\) in fig.

1 \(r\)
2 \(2 r\)
3 \(4 r\)
4 \(r / 2\)
Current Electricity

268474 The resistance of a platinum wire of a platinum resistance thermometer at the ice point is\(5 \Omega\) and at steam point is \(5.4 \Omega\). When the thermometer is inserted in a hot bath, the resistance of the platinum wire is \(6.2 \Omega\). Find the temperature of the hot bath.

1 \(3000^{\circ} \mathrm{C}\)
2 \(30^{\circ} \mathrm{C}\)
3 \(300^{\circ} \mathrm{C}\)
4 \(300 \mathrm{~K}\)
Current Electricity

268475 Three unequal resistors in parallel are equivalent to a resistance 1 ohm. If two of them are in the ratio\(1: 2\) and if no resistance value is fractional, the largest of the three resistance in ohm is

1 4
2 6
3 8
4 12
Current Electricity

268476 A carbon filament has resistance of\(120 \Omega\) at \(0^{\circ} \mathrm{C}\) what must be the resistance of a copper filament connected in series with carbon so that combination has same resistance at all temperatures
\(\begin{aligned}
& \left(\alpha_{\text {carton }}=-5 \times 10^{-4} /{ }^{\circ} \mathrm{C}, \alpha_{\text {copper }}=4 \times 10^{-3} /{ }^{\circ} \mathrm{C}\right) \\
& \begin{array}{llll}
\text { 1) } 120 \Omega & \text { 2) } 15 \Omega & \text { 3) } 60 \Omega & \text { 4) } 210 \Omega
\end{array}
\end{aligned}\)

1 \(120 \Omega\)
2 \(15 \Omega\)
3 \(60 \Omega\)
4 \(210 \Omega\)
Current Electricity

268477 Theequivalent resistance across \(X Y\) in fig.

1 \(r\)
2 \(2 r\)
3 \(4 r\)
4 \(r / 2\)