Electromagnetic waves travel in a medium which has relative permeability 1.3 and relative permittivity 2.14. Then the speed of the electromagnetic wave in the medium will be
|
(a) 13.6 |
(b) 1.8 |
(c) 3.6 |
(d) 1.8 |
(d) 1.8 
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A rectangular loop is being pulled at a constant speed v, through a region of certain thickness d, in which a uniform magnetic field B is set up. The graph between position x of the right hand edge of the loop and the induced emf E will be
(a)
|
(b)
|
(c)
|
(d)
|
A double convex lens (
having focal length equal to the focal length of a concave mirror. The radius of curvature of the concave mirror is
|
(a) 10 cm |
(b) 20 cm |
(c) 40 cm |
(d) 15 cm |
An electron has mass 9 
and charge 1.6 
is moving with a velocity of 
, enters a region where magnetic field exists. If it describes a circle of radius 0.10 m, the intensity of magnetic field must be
|
(a) 1.8 |
(b) 5.6 |
(c) 14.4 |
(d) 1.3 |
The potential difference applied to an X-ray tube is 5kV and the current through it is 3.2 mA. Then the number of electrons striking the target per second is
|
(a) 2 |
(b) 5 |
(c) 1 |
(d) 4 |
Half-life of a radioactive substance is 20 minutes. Difference between points of time when it is 33% disintegrated and 67% disintegrated is approximately
|
(a) 10 min |
(b) 20 min |
(c) 30 min |
(d) 40 min |
A magnet is suspended in the magnetic meridian with an untwisted wire. The upper end of wire is rotated through 180o to deflect the magnet by 30o from magnetic meridian. When this magnet is replaced by another magnet, the upper end of wire is rotated through 270o to deflect the magnet 30o from magnetic meridian. The ratio of magnetic moments of magnets is
|
(a) 1 : 5 |
(b) 1 : 8 |
(c) 5 : 8 |
(d) 8 : 5 |
