The current sensitivity of a Galvanometer can be increased by decreasing-
a) Magnetic field B
b) No. of turns N
c) Torsional constant k
d) Area of the coil A
a) Magnetic field B
b) No. of turns N
c) Torsional constant k
d) Area of the coil A
c) Torsional constant k
What is the shape of the magnet in Moving Coil Galvanometer to make the torque maximum?
a) Horse Shoe
b) Convex
c) Concave
d) None of these.
A solenoid has 1000 turns per metre length. If a current of 5A is flowing through it, then magnetic field inside the solenoid is-
If distance between two current- carrying wires is doubled, then force between them is
(a) halved
(b) doubled
(c) tripled
(d) quadrupled.
Two wires of same length are shaped into a square and a circle. If they carry same current, the ratio of their magnetic moment-
a) 2:π
b)π:2
c) 4:π
d) π:4.
The coil of a moving coil galvanometer is wound over a metal frame in order to-
(a) reduce hysteresis
(b) increase sensitivity
(c) increase moment of inertia
(d) provide electromagnetic damping.
The magnetic field at an outside point due to a long straight conductor carrying a constant current(I) is independent of
a) Material of the conductor
b) Radius of the conductor
c) Both (a) and (b)
d) Neither (a) nor (b)
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
A young’s double slit experiment uses a monochromatic source. The shape of interference fringes formed on a screen is :
a. Parabola
b. straight line
c. circle
d. Hyperbola
The main condition for diffraction to be observed is
a. Size of obstacle should be much smaller than the wavelength of the wave.
b. Size of obstacle should be much larger than the wavelength of the wave.
c. Size of the obstacle should be comparable to the wavelength of the wave.
d. For any size of the obstacle.
In an A.C. circuit, Irms and I₀ are related as
(a) Irms = p I₀
(b) Irms = 2 I₀
(c) Irms = I₀/p
(d) Irms =I₀ / 2
Polaroid glasses is used in sun glasses because :
a. It reduces the light intensity to half on account of polarization
b. It is fashionable
c. It has good colour
d. It is cheaper
A compass needle whose magnetic moment is 60 A m² pointing geographical north at a certain place, where the horizontal component of the earth’s magnetic field is 40 μWb m², experiences a torque
0.2 × 10⁻³ Nm. The declination at this place is
When tiny circular obstacle is placed in the path of light from a distance source , a bright spot is seen at the centre of the obstacle.
I. It happens due to
II. Polarization of light waves
III. Diffraction of light waves
IV. Interference of light waves
V. Scattering of light waves