Current Electricity

The power dissipated in the transmission cables carrying current I and voltage V is inversely proportional to

• V

• V²

• $\sqrt{\mathrm{V}}$

• $\sqrt{\mathrm{I}}$

In the network shown below, if potential across XY is 4 V, then the input potential across AB is

• 16 V

• 20 V

• 8 V

• 12 V

If the ammeter A shows a zero reading in the circuit shown below, the value of resistance R is

• 500 Ω

• 125 Ω

• 100 Ω

• 41.5 Ω

Resistance of 12 Ω and X Ω are connected in parallel in the left gap and resistances of 9 Ω and 7 Ω are connected in series in the right gap of the meter bridge. If the balancing length is 36 cm, then the value of resistance X is

• 72 Ω

• 54 Ω

• 36 Ω

• 64 Ω

Ten identical batteries each of emf 2 V are connected in series to a 8 Ω resistor. If the current in the circuit is 2 A, then the internal resistance of each battery is

• 0.2 Ω

• 0.3 Ω

• 0.4 Ω

• 0.5 Ω

In a potentiometer of wire length l, a cell of emf V is balanced at a length $\frac{\mathrm{l}}{3}$ from the positive of the wire. For another cell of emf 1.5 V, the balancing length becomes

• $\frac{\mathrm{l}}{6}$

• $\frac{\mathrm{l}}{2}$

• $\frac{\mathrm{l}}{3}$

• $\frac{2\mathrm{l}}{3}$

The smallest resistance that can be obtained by combining 10 resistors each of resistance 10 Ω is

• 10 Ω

• 0.5 Ω

• 1 Ω

• 20 Ω

Pick out the wrong statement from the following

• The SI unit of conductance is mho

• Conductance of a conductor decreases with increase in temperature

• The relation between voltage and current for a non-ohmic conductor is linear

• If the length of the metallic wire is doubled, its resistivity remains unchanged

A given resistor has the following colour code of the various strips on it : Brown, black, green and silver. The value of its resistance in ohm is

• 1.0 × 10⁴ ± 10 %

• 1.0 × 10⁷ ± 5 %

• 1.0 × 10⁶ ± 10 %

• 1.0 × 10⁵ ± 5 %

If an ideal junction diode is connected as shown, then the value of the current i is

• 0.013 A

• 0.02 A

• 0.01 A

• 0.1 A