- AIron
- BSilver
- CCopper
- DCarbon
Explanation:
Silver is the best conductor of electricity because it contains maximum number of free electrons.
Also the resistance of silver is very low.
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The ratio of the magnetic field at the centre of a current carrying coil of the radius a and at a distance ‘a’ from centre of the coil and perpendicular to the axis of coil is
|
(a) |
(b) |
(c) |
(d) 2 |
A magnet of magnetic moment M and pole strength m is divided in two equal parts, then magnetic moment of each part will be
|
(a) M |
(b) M/2 |
(c) M/4 |
(d) 2M |
The intensity of gamma radiation from a given source is I. On passing through 36 mm of lead, it is reduced to
. The thickness of lead which will reduce the intensity to
will be
|
(a) 18 mm |
(b) 12 mm |
(c) 6 mm |
(d) 9 mm |
Light wave is travelling along y-direction. If the corresponding
vector at any time is along the x-axis, the direction of
vector at that time is along

|
(a) y-axis |
(b) x-axis |
(c) + z-axis |
(d) – z axis |
Assertion : A laser beam 0.2 W power can drill holes through a metal sheet, whereas 1000 W torch-light cannot.
Reason : The frequency of laser light is much higher then that of torch light.
|
(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. |