Intrinsic semiconductor is electrically neutral. Extrinsic semiconductor having large number of current carriers would be
|
(a) Positively charged |
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(b) Negatively charged |
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(c) Positively charged or negatively charged depending upon the type of impurity that has been added |
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(d) Electrically neutral |
(d) Electrically neutral
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AM is used for broadcasting because
|
(a) It is more noise immune than other modulation systems |
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(b) It requires less transmitting power compared with other systems |
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(c) Its use avoids receiver complexity |
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(d) No other modulation system can provide the necessary bandwidth faithful transmission |
A capacitor is charged by using a battery which is then disconnected. A dielectric slab is then slipped between the plates, which results in
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(a) Reduction of charge on the plates and increase of potential difference across the plates |
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(b) Increase in the potential difference across the plate, reduction in stored energy, but no change in the charge on the plates |
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(c) Decrease in the potential difference across the plates, reduction in the stored energy, but no change in the charge on the plates |
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(d) None of the above |
Assertion : The refractive index of diamond is 
and that of liquid is 
. If the light travels from diamond to the liquid, it will totally reflected when the angle of incidence is 30o.
Reason : μ = 
where m is the refractive index of diamond with respect to liquid.
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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 assertion is false but reason is true. |
In case of linearly polarized light, the magnitude of the electric field vector :
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(a) Does not change with time |
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(b) Varies periodically with time |
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(c) Increases and decreases linearly with time |
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(d) Is parallel to the direction of propagation |
The focal lengths for violet, green and red light rays are 
and 
respectively. Which of the following is the true relationship
|
(a) |
(b) |
(c) |
(d) |
Assertion : Short wave bands are used for transmission of ratio waves to a large distance
Reason : Short waves are reflected by ionosphere
|
(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. |
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(c) If assertion is true but reason is false. |
| (d) If assertion is false but reason is true. |
The relaxation time in conductors
|
(a) Increases with the increase of temperature |
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(b) Decreases with the increase of temperature |
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(c) It does not depend on temperature |
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(d) All of sudden changes at 400 K |
