When a bar magnet falls through a long hollow metal cylinder fixed with its axis vertical, the final acceleration of the magnet is
|
(a) Equal to zero |
|
(b) Less than g |
|
(c) Equal to g |
|
(d) Equal to g in to beginning and then more than g |
(a) Equal to zero
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Two wires of same material have length L and 2L and cross–sectional areas 4A and A respectively. The ratio of their specific resistance would be
|
(a) 1 : 2 |
(b) 8 : 1 |
(c) 1 : 8 |
(d) 1 : 1 |
Peltier co-efficient of a thermo couple is 2 nano volts. How much heat is developed at a junction if 2.5 amp current flows for 2 minute
|
(a) 6 ergs |
(b) 6 |
(c) 16 ergs |
(d) 6 |
$\frac{1}{2}\text{kx}^2$
$-\frac{1}{2}\text{kx}^2$
$\frac{1}{4}\text{kx}^2$
$-\frac{1}{4}\text{kx}^2$
Two lenses of power 6D and – 2D are combined to form a single lens. The focal length of this lens will be
|
(a) |
(b) |
(c) 4 m |
(d) |
Electromotive force is the force, which is able to maintain a constant
|
(a) Current |
(b) Resistance |
(c) Power |
(d) Potential difference |
The minimum wavelength of X-rays produced by electrons accelerated by a potential difference of volts is equal to
(a) 
|
(b) 
|
(c) 
|
(d) 
|
A circular coil having N turns is made from a wire of length L meter. If a current I ampere is passed through it and is placed in a magnetic field of B Tesla, the maximum torque on it is
|
(a) Directly proportional to N |
(b) Inversely proportional to N |
|
(c) Inversely proportional to |
(d) Independent of N |
A coil of wire of a certain radius has 600 turns and a self inductance of 108 mH. The self inductance of a 2nd similar coil of 500 turns will be
|
(a) 74 mH |
(b) 75 mH |
(c) 76 mH |
(d) 77 mH |
