A wire of length L and 3 identical cells of negligible internal resistances are connected in series. Due to current, the temperature of the wire is raised by ΔT in a time t. A number N of similar cells is now connected in series with a wire of the same material and cross–section but of length 2 L. The temperature of the wire is raised by the same amount ΔT in the same time t. The value of N is- 

(1) 4

(2) 6

(3) 8

(4) 9

What is the equivalent resistance between terminals \(A\) and \(B\) of the network?

The effective resistance between points \(P\) and \(Q\) of the electrical circuit shown in the figure is:

In the circuit element given here, if the potential at point B, V_B = 0, then the potentials of A and D are given as 

(1) $V_A=-1.5V,V_D=+2V$

(2) $V_A=+1.5V,V_D=+2V$

(3) $V_A=+1.5V,V_D=+0.5V$

(4) $V_A=+1.5V,V_D=-0.5V$

The current in a conductor varies with time t as $I=2t+3t^2$ where I is in ampere and t in seconds. The electric charge flowing through a section of the conductor during t = 2 sec to t = 3 sec is :

(1) 10 C

(2) 24 C

(3) 33 C

(4) 44 C

In the shown arrangement of the experiment of the meter bridge if AC corresponding to null deflection of galvanometer is x, what would be its value if the radius of the wire AB is doubled 

(1) x

(2) x/4

(3) 4x

(4) 2x

Seven resistances are connected as shown in the figure. The equivalent resistance between A and B is 

(1) 3 Ω

(2) 4 Ω

(3) 4.5 Ω

(4) 5 Ω

A battery of internal resistance 4Ω is connected to the network of resistances as shown. In order to give the maximum power to the network, the value of R (in Ω) should be :

(1) 4/9

(2) 8/9

(3) 2

(4) 18

In the circuit shown here, the readings of the ammeter and voltmeter are

(1) 6 A, 60 V

(2) 0.6 A, 6 V

(3) 6/11 A, 60/11 V

(4) 11/6 A, 11/60 V

A wire of resistor R is bent into a circular ring of radius r. Equivalent resistance between two points X and Y on its circumference, when angle XOY is α, can be given by

(1) $\frac{R\alpha }{4{\pi }^2}(2\pi -\alpha )$

(2) $\frac{R}{2\pi }(2\pi -\alpha )$

(3) R (2π – α)

(4) $\frac{4\pi }{R\alpha }(2\pi -\alpha )$