Cathode rays travelling from west to east enter into region of electric field directed towards south to north in the plane of paper. The deflection of cathode rays is towards:
(A) East
(B) West
(C) North
(D) South
(A) East
(B) West
(C) North
(D) South
(D) South
What is the angle between the electric dipole moment and electric field strength due to it on the axial line?
(A) \(0^\circ\)
(B) \(90^\circ\)
(C) \(180^\circ\)
(D) None of these
Two-point charges 2μC and 4μC are placed 2 cm apart. The ratio of the Coulomb’s force experienced by them is
(A) 1: 2
(B) 2: 1
(C) 1: 1
(D) 4: 1
the magnitude of a charge q at the center of two equal and like charges Q so that the three charges are in equilibrium
A. Q
B. Q/2
C. Q/4
D. –Q/4
Derive an expression for electric field of a dipole at a point on the equatorial plane of the dipole. How does the field vary at large distances?
When 2 × \(10^{11}\) electrons are removed from a neutral metal sphere, the charge on the sphere becomes:
(A) -16 nC
(B) 16 nC
(C) -32 nC
(D) 32nC
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
Two balls carrying charges - and +8 attract each other with a force F. If a charge of -3 is added to both the balls, then the force between then will become
A. 2F
B. F/2
C. F
D. zero
Two sources of light are said to be coherent when both give out light waves of the same:
(a) amplitude and phase.
(b) intensity and wavelength.
(c) speed.
(d) wavelength and a constant phase difference.
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 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
What is the effect on the angular width of interference fringes in a Young’s double slit experiment when the screen moved near to the plane of slits.
(a) increases
(b) decreases
(c) constant
(d) not defined
The wavefront due to a source situated at infinity is
(a) spherical
(b) cylindrical
(c) planar
(d) circular
The following figure shows the top view of a rod that can slide without friction. The resistance is 5.0Ω and a 2.5 T magnetic field is directed perpendicularly downwards into the paper. Length of the rod is 1.0 m.
The angle of incidence at which reflected light is totally polarised for reflection from air to glass (refractive index n) is