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
(a) 0.25 Ω
(b) 0.4 Ω
(c) 0.5 Ω
(d) 4 Ω
(a) 0.25 Ω
Five resistances are combined according to the figure. The equivalent resistances between the points X and Y will be
(a) 10 Ω
(b) 22 Ω
(c) 20 Ω
(d) 50 Ω
A new flashlight cell of emf 1.5 volts gives a current of 15 amps, when connected directly to an ammeter of resistance 0.04 Ω. The internal resistance of cell is
(a) 0.04 Ω
(b) 0.06 Ω
(c) 0.10 Ω
(d) 10 Ω
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
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 torch bulb rated as 4.5 W, 1.5 V is connected as shown in the figure. The emf of the cell needed to make the bulb glow at full intensity is
(a) 4.5 V
(b) 1.5 V
(c) 2.67 V
(d) 13.5 V
In the circuit shown in the figure, find the total resistance of the circuit and the current in the arm CD.
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.
The wavefront due to a source situated at infinity is
(a) spherical
(b) cylindrical
(c) planar
(d) circular
In young’s double slit experiment slits are separated by 0.32mm, and screen is at 1.6m away. Then find out the least distance from the central bright fringe where the bright fringes of wavelengths as 800nm and 600nm are coinciding.
(A) 10mm
(B) 12mm
(C) 1.2mm
(D) 1.0mm
An optically active compound
(a) rotates the plane of polarised light
(b) changes the direction of polarised light
(c) does not allow plane polarised light to pass through
(d) none of these
The ratio of magnetic length to geometric length of a magnet is
a) 0.084
b) 8.4
c) 80.4
d) 0.84
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.
\(10^6\) electrons are taken out of a pith ball. The positive charges on the pith ball is
A. 1.6x \(10^{-13}\) C
B. 1.6x \(10^{-19}\) C
C. 1.6x \(10^{-25}\) C
D. none of these
Ratio of intensities of two waves are given by 4 :1. Then the ratio of the amplitudes of the two waves.
(a) 2 : 1
(b) 1 : 2
(c) 4 : 1
(d) 1 : 4