Two sources give interference pattern which is observed on a screen, D distance apart from the sources. The fringe width is 2w. If the distance D is now doubled, the fringe width will
|
(a) Become w/2 |
(b) Remain the same |
(c) Become w |
(d) Become 4w |
(d) Become 4w
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In vacuum an electron of energy 10 keV hits tungsten target, then emitted radiation will be
|
(a) Cathode rays |
(b) X-rays |
(c) Infrared rays |
(d) Visible spectrum |
Tangent galvanometer is used to measure
| (a) Steady currents | (b) Current impulses |
| (c) Magnetic moments of bar magnets | (d) Earth's magnetic field |
A radioactive material has a half-life of 8 years. The activity of the material will decrease to about 1/8 of its original value in
|
(a) 256 year |
(b) 128 year |
(c) 64 year |
(d) 24 year |
Two opposite and equal charges 4 × 
when placed 2 
cm away, form a dipole. If this dipole is placed in an external electric field 4 
, the value of maximum torque and the work done in rotating it through 180° will be
|
(a) 64 |
(b) 32 |
|
(c) 64 |
(d) 32 |
The energy stored in the condenser is
|
(a) QV |
(b) |
(c) |
(d) |
