An ammeter, voltmeter and a resistor are connected in series to a cell and the readings are noted as I and V. If another resistor R is connected in parallel with voltmeter, then

• I and V increase

• I increases

• I and V will remain same

• I decreases

One gram of copper is deposited in a copper voltameter when a current of 0.5 A flows for 30 minutes. Then, the current required to deposit 2g of silver in a silver voltmeter in the same time is (ece of copper = 3.3x10^-4 gC^-1, ece of silver = 1.1 x 10^-4 gC^-1)

• 4 A

• 6 A

• 3 A

• 5 A

43.

The amount of charge flowing per second per unit area normal to the flow is called

• electrical conductivity

• electrical resistivity

• mobility

• current density

A galvanometer of resistance G is converted into an ammeter using a shunt of resistance R. If the ratio of the heat dissipated through the galvanometer and shunt is 3 : 4, then R equals

• $\frac{4}{3} \mathrm{G}$

• $\frac{3}{4} \mathrm{G}$

• $\frac{16}{9} \mathrm{G}$

• $\frac{9}{16} \mathrm{G}$

Two bulbs of equal power are connected in parallel and they totally consume 110 W at 220 V. The resistances of each bulb is

• 550 Ω

• 440 Ω

• 330 Ω

• 880 Ω

The wire of length l is bent into a circular loop of a single turn and is suspended in a magnetic field of induction B. When a current I is passed. through the loop, the maximum torque experienced by it is

• $\left(\frac{1}{4\mathrm{\pi }}\right)$ BIl²

• $\frac{1}{4\mathrm{\pi }}$ BI²l

• $\left(\frac{1}{4\mathrm{\pi }}\right)$ BIl

• $\left(\frac{1}{4\mathrm{\pi }}\right)$ B²Il

A particle having charge 10 times that of the electron revolves in a circular path of radius 0.4 m with an angular speed of one rotation per second. The magnetic induction produced at the centre of the circular path is

• $4\mathrm{\pi } \times {10}^{-26} \mathrm{T}$

• $2\mathrm{\pi } \times {10}^{-26} \mathrm{T}$

• $16\mathrm{\pi } \times {10}^{-26} \mathrm{T}$

• $8\mathrm{\pi } \times {10}^{-25} \mathrm{T}$

Pick out the wrong statement among the following.

• Time varying magnetic field creates an electric field

• Charges in motion can exert force on a stationary magnet

• Stationary charges can exert torque on a stationary magnet

• A bar magnet in motion can exert force on a stationary charge

If a magnet is plugged into a coil, then the magnitude of induced emf does not depend upon

• the number of turns in the coil

• the medium of the core of the coil

• the resistance of the coil

• the strength of the magnet

If 0.1 J of energy is stored for the flow of current of 0.2 A in an inductor, then its inductance value is

• 5 H

• 0.5 H

• 5 mH

• 50 H