Explanation:
Electric field due to Q & q, inside the spherical shell is zero.
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If in a plano-convex lens, the radius of curvature of the convex surface is 10 cm and the focal length of the lens is 30 cm, then the refractive index of the material of lens will be
|
(a) 1.5 |
(b) 1.66 |
(c) 1.33 |
(d) 3 |
According to Gauss’ Theorem, electric field of an infinitely long straight wire is proportional to
|
(a) r |
(b) |
(c) |
(d) |
When hydrogen atom is in its first excited level, its radius is .... its ground state radius
|
(a) Half |
(b) Same |
(c) Twice |
(d) Four times |
A galvanometer can be converted into an ammeter by connecting
|
(a) Low resistance in series |
(b) High resistance in parallel |
|
(c) Low resistance in parallel |
(d) High resistance in series |
There are 
photons of frequency 
in a beam of light. In an equally energetic beam, there are 
photons of frequency 
. Then the correct relation is
|
(a) |
(b) |
(c) |
(d) |
Two thick wires and two thin wires, all of the same materials and same length form a square in the three different ways P, Q and R as shown in fig with current connection shown, the magnetic field at the centre of the square is zero in cases
|
(a) In P only |
(b) In P and Q only |
(c) In Q and R only |
(d) P and R only |
A player with 3 m long iron rod runs towards east with a speed of 30 km/hr. Horizontal component of earth's magnetic field is 4 
. If he is running with rod in horizontal and vertical positions, then the potential difference induced between the two ends of the rod in two cases will be
|
(a) Zero in vertical position and 1 |
|
(b) 1 |
|
(c) Zero in both cases |
|
(d) 1 |
