- Aremains unchanged
- ✓decreases
- Cincreases
- Dfirst decreases and then increases
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Photo cell is a device to
|
(a) Store photons |
|
(b) Measure light intensity |
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(c) Convert photon energy into mechanical energy |
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(d) Store electrical energy for replacing storage batteries |
Three observers A, B and C measure the speed of light coming from a source to be
and
. The observer A moves towards the source, the observer C moves away from the source with the same speed. The observer B stays stationary. the surrounding space is vacuum every where. Then
|
(a) |
(b) |
(c) |
(d) |
$\text{mgvt}\cos^2\theta$
$\text{mgvt}\sin^2\theta$
$\text{mgvt}\sin2\theta$
Energy of electron in a orbit of H-atom is
|
(a) Positive |
(b) Negative |
(c) Zero |
(d) Nothing can be said |
Which of the following graphs shows the variation of magnetic induction B with distance r from a long wire carrying current
|
(a) |
(b) |
(c) |
(d) |
Assertion : An electric field is preferred in comparison to magnetic field for detecting the electron beam in a television picture tube.
Reason : Electric field require low voltage.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |