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.
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.
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 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
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.
A Galvanometer is said to be sensitive, when-
a) Small deflection for a small current
b) Small deflection for a large current
c) large deflection for a small current
d) large deflection for a large current .
When ordinary light is made incident on a quarter wave plate, the emergent light is
(a) linearly polarised.
(b) circularly polarised.
(c) unpolarised.
(d) elliptically polarised.
If a charge q is placed at the center of the line joining two equal charges Q such that the system is in equilibrium, then the value of q is
(A)Q/2
(B)-Q/2
(C)Q/4
(D)-Q/4
A current loop placed in a magnetic field behaves like a
a) Magnetic substance
b) Magnetic pole
c) Magnetic dipole
d) all true
If the width of the slit in single slit diffraction experiment is doubled, then the central maximum of diffraction pattern becomes:
(A) broader and brighter
(B) broader and fainter
(C) sharper and fainter
(D) sharper and brighter
Electric flux emanating through a surface element placed in an electric field is
(A) 10 units
(B) 20 units
(C) 4 units
(D) 16 units
The angle of incidence at which reflected light is totally polarised for reflection from air to glass (refractive index n) is