nucleus after absorbing energy decays into two α - particles and an unknown nucleus. The unknown nucleus is
|
(a) Nitrogen |
(b) Carbon |
(c) Boron |
(d) Oxygen |
(b) Carbon
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A nucleus of an element 
emits an a-particle first, a b-particle next and then a gamma photon. The final nucleus formed has an atomic number
|
(a) 200 |
(b) 199 |
(c) 83 |
(d) 198 |
An eye specialist prescribes spectacles having a combination of convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. The power of this lens combination in diopters is
|
(a) + 1.5 |
(b) – 1.5 |
(c) + 6.67 |
(d) – 6.67 |
X-rays are
| (a) Stream of electrons |
| (b) Stream of positively charged particles |
| (c) Electromagnetic radiations of high frequency |
| (d) Stream of uncharged particles |
The ground state energy of hydrogen atom is – 13.6 eV. What is the potential energy of the electron in this state
| (a) 0 eV | (b) – 27.2 eV | (c) 1 eV | (d) 2 eV |
Two equal point charges are fixed at x = -a and x = +a on the x-axis. Another point charge Q is placed at the origin. The Change in the electrical potential energy of Q, when it is displaced by a small distance x along the x-axis, is approximately proportional to
|
(a) x |
(b) |
(c) |
(d) 1/x |
If a magnet of length 10 cm and pole strength 40 A-m is placed at an angle of 45o in an uniform induction field of intensity 2 × 10–4 T, the couple acting on it is
|
(a) 0.5656 × 10–4 N-m |
(b) 0.5656 × 10–3N-m |
(c) 0.656 × 10–4 N-m |
(d) 0.656 × 10–5 N-m |
The length of the wire is doubled. Its conductance will be
|
(a) Unchanged |
(b) Halved |
|
(c) Quadrupled |
(d) 1/4 of the original value |
The wavelength of Lyman series is
|
(a) |
(b) |
(c) |
(d) |
A small bar magnet A oscillates in a horizontal plane with a period T at a place where the angle of dip is 60o. When the same needle is made to oscillate in a vertical plane coinciding with the magnetic meridian, its period will be
(a) 
|
(b) T |
(c) 
|
(d) 2T |
