A resistance of R Ω draws current from a potentiometer. The potentiometer has a total resistance \(R_0\) Ω as shown in the Fig below. A voltage V is supplied to the potentiometer. Derive an expression for the voltage across R when the sliding contact is in the middle of the potentiometer.
A network of resistors is connected to a 16 V battery with internal resistance of 1Ω as shown in the Fig. Compute the equivalent resistance of the network.
(a) 5 ohm
(b) 7 ohm
(c) 9 ohm
(d) 10 ohm
A network of resistors is connected to a 16 V battery with internal resistance of 1 Ω, as shown in the following figure. Compute the equivalent resistance of the network.
Define relaxation time of the free electrons drifting in a conductor. How is it related to the drift velocity of free electrons ? Use this relation to deduce the expression for the electrical resistivity of the material.
Two cells of emfs E₁ & E₂ and internal resistances r₁ & r₂ respectively are connected in parallel. Obtain expressions for the equivalent.
(i) resistance and
(ii) emf of the combination
A battery of emf 10 V and internal resistance 3 ohm is connected to a resistor. If the current in the circuit is 0.5 A, find :
(i) the resistance of the resistor;
(ii) the terminal voltage of the battery.
A 9 V battery is connected in series with a resistor. The terminal voltage is found to be 8 V. Current through the circuit is measured as 5 A. What is the internal resistance of the battery?
A cell of emf 4 V and internal resistance 1 W is connected to a d.c. source of 10 V through a resistor of 5 W. Calculate the terminal voltage across the cell during charging.
The V-i graph for a conductor at temperature T¹ and T² are as shown in the figure. (T² - T¹) is proportional to
(a) cos θ
(b) sin θ
(c) cot 2θ
(d) tan θ
A wavefront of a wave has direction with wave motion
(A) Parallel
(B) Perpendicular
(C) opposite
(D) at any angle θ
A coil of wire of certain radius has 500 turns and self inductance of 75 mH. The self inductance of a second similar coil of 600 turns will be
(a) 100 mH
(b) 150mH
(c) 108 mH
(d) 105mH
The colours on the soap bubble is due to
(a) Interference
(b) Diffraction
(c) Polarisation
(d) Reflection
In Young’s double slit experiment, the central point on the screen is:
a. Bright
b. Dark
c. First bright and later dark
d. First dark and later bright
When light suffers reflection at the interface between water and glass, the change of phase in the reflected wave is
(a) zero..
(b) π.
(c) π/2.
(d) 2π.
In meter bridge, the balancing length from left end when standard resistance of 1 Ω is in right gap is found to be 20 cm. The value of unknown resistance is
(a) 0.25 Ω
(b) 0.4 Ω
(c) 0.5 Ω
(d) 4 Ω