A diminished virtual image can be formed only in
|
(a) Plane mirror |
(b) A concave mirror |
|
(c) A convex mirror |
(d) Concave-parabolic mirror |
A diminished virtual image can be formed only in
|
(a) Plane mirror |
(b) A concave mirror |
|
(c) A convex mirror |
(d) Concave-parabolic mirror |
(c) A convex mirror
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Fusion reaction takes place at high temperature because
|
(a) Atoms are ionised at high temperature |
|
(b) Molecules break-up at high temperature |
|
(c) Nuclei break-up at high temperature |
|
(d) Kinetic energy is high enough to overcome repulsion between nuclei |
Two identical magnetic dipoles of magnetic moments 1.0 A-m2 each, placed at a separation of 2m with their axis perpendicular to each other. The resultant magnetic field at a point midway between the dipoles is
|
(a) 5 |
(b) |
(c) |
(d) None of these |
A metallic surface with work function of 2 eV, on heating to a temperature of 800 K gives an emission current of 1 mA. If another metallic surface having the same surface area, same emission constant but work function 4 eV is heated to a temperature of 1600 K, then the emission current will be
|
(a) 1 mA |
(b) 2 mA |
(c) 4 mA |
(d) None of these |
A nucleus of mass 218 amu in free state decays to emit an a-particle. Kinetic energy of the a-particle emitted is 6.7 MeV. The recoil energy (in MeV) of the daughter nucleus is
|
(a) 1.0 |
(b) 0.5 |
(c) 0.25 |
(d) 0.125 |