A, B and C are voltmeters of resistance R, 1.5 R  and 3R respectively as shown in the figure. When some potential difference is applied between X and Y, the voltmeter readings are V_A, V_B and V_c respectively then,

• V_A =V_B =V_c

• 
• 
• 

The power dissipated in the circuit shiwn in the figure is 30 Watt. The value of R is

• 20 Ω

• 15Ω

• 10Ω

• 10Ω

A cell having an emf and internal resistance r is connected across a variable external resistance R. As the resistance R is increased, the plot of potential difference V across R is given by

224.

In an electrical circuit R, L, C and AC voltage source are all connected in series when L is removed from the circuit, the phase difference between the voltage and the current in the circuit is π/3. If instead, Cis removed from the circuit, the phase difference is again π/3. The power factor of the circuit is

• 1/2

• 

• 1

• 1

A millivoltmeter of 25 mV range is to be converted into an ammeter of 25 A range. The value (in ohm) of necessary shunt will be

• 0.001

• 0.01

• 1

• 1

A ring is made of wire having a resistance R_o = 12Ω. Find the points A and B, as shown in the figure, at which a current carrying conductor should be connected so that the resistance R of the subcircuit between these points is equal to 8/3Ω

The resistances in the two arms of the meter bridge are 5 ohm and R ohm, respectively. When the resistance  R is shunted with an equal resistance, the new balance point is at 1.6 l₁. The resistance R is,

• 10 ohm

• 15 ohm

• 20 ohm

• 20 ohm

A potentiometer circuit has been set up for finding the internal resistance of a given cell. The main battery, used across the potentiometer wire, has an emf of 2.0 V and a negligible internal resistance. The potentiometer wire itself is 4 m long. When the resistance R, connected across the given cell, has values of i) infinity ii) 9.5 ohm the balancing lengths on the potentiometer wire are found to be 3 m and 2.85 m, respectively. The value of internal resistance of the cell is,

• 0.25 ohm

• 0.95 ohm

• 0.5 ohm

• 0.5 ohm

In an ammeter 0.2 % of the main current passes through the galvanometer. If resistance of galvanometer is G, the resistance of ammeter will be,

• 1/499 G

• 499/500 G

• 1/500 G

• 1/500 G

In the circuit shown the cells A and B have negligible resistances. For V_A = 12V, R₁ = 500Ω and R = 100Ω the galvanometer (G) shows no deflection. The value of V_B is

• 4V

• 2V

• 12 V

• 12 V