- AThe electric field must not be zero.
- BThe magnetic field must not be zero.
- CThe electric field may or may not be zero.
- DThe magnetic field may or may not be zero.
Explanation:
Since particle is at rest, i.e. v=0, hence Fm=0
For electric force, E≠0
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A moving coil galvanometer has 150 equal divisions. Its current sensitivity is 10 divisions per milliampere and voltage sensitivity is 2 divisions per millivolt. In order that each division reads 1 volt, the resistance in ohms needed to be connected in series with the coil will be
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(a) 99995 |
(b) 9995 |
(c) |
(d) |
Assertion : The speed of light in a rarer medium is greater than that in a denser medium
Reason : One light year equals to 9.5 × 1012 km
|
(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. |
When white light passes through the achromatic combination of prisms, then what is observed
|
(a) Only deviation |
(b) Only dispersion |
|
(c) Deviation and dispersion |
(d) None of the above |
Cathode rays are produced when the pressure is of the order of
|
(a) 2 cm of Hg |
(b) 0.1 cm of Hg |
(c) 0.01 mm of Hg |
(d) 1 μm of Hg |
Four capacitors are connected as shown in the equivalent capacitance between the points P and Q is
|
(a) 4 μF |
(b) |
(c) |
(d) |

In good conductors of electricity, the type of bonding that exists is
|
(a) Ionic |
(b) Vander Waals |
(c) Covalent |
(d) Metallic |
The terminal potential difference of a cell when short-circuited is (E = E.M.F. of the cell)
|
(a) E |
(b) E/2 |
(c) Zero |
(d) E/3 |