There is an air filled 1 pF parallel plate capacitor. When the plate separation is doubled and the space is filled with wax, the capacitance increases to 2pF. The dielectric constant of wax is
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(a) 2 |
(b) 4 |
(c) 6 |
(d) 8 |
(b) 4
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Assertion : X-rays cannot be diffracted by means of grating.
Reason : X-rays does not obey Bragg's law.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
The magnifying power of a simple microscope can be increased if we use an eyepiece of:
The chemical equivalent of silver is 108. If the current in a silver voltameter is 2 Amp., the time required to deposit 27 grams of silver will be
|
(a) 8.57 hrs |
(b) 6.70 hrs |
(c) 3.35 hrs |
(d) 12.50 hrs |
Resistances 
and 
are joined in parallel and a current is passed so that the amount of heat liberated is 
and 
respectively. The ratio 
has the value
|
(a) |
(b) |
(c) |
(d) |
In ballistic galvanometer, the frame on which the coil is wound is non-metallic to
|
(a) Avoid the production of induced e.m.f. |
(b) Avoid the production of eddy currents |
|
(c) Increase the production of eddy currents |
(d) Increase the production of induced e.m.f. |
If a lens is cut into two pieces perpendicular to the principal axis and only one part is used, the intensity of the image
|
(a) Remains same |
(b) |
(c) 2 times |
(d) Infinite |
