MCQ
If an object is positively charged, theoretically the mass of the object ______?
- AIncreases slightly by a factor of 9.11 × 10-31kg.
- BDecreases slightly by a factor of 9.11 × 10-31kg.
- CRemains the same.
- DMay increase or decrease.
Explanation:
If an object is positively charged it loses some of its electrons. The mass of an electron is 9.11 × 10-31kg. So, if a positively charged body loses ‘n’ number of electrons, it mass decrease by the amount n × 9.11E-31kg.
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In which of the following ionic bond is present
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(a) NaCl |
(b) Ar |
(c) Si |
(d) Ge |
The focal length of the objective lens of a compound microscope is
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(a) Equal to the focal length of its eye piece |
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(b) Less than the focal length of eye piece |
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(c) Greater than the focal length of eye piece |
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(d) Any of the above three |
Assertion : If different gases are filled turn by turn at the same pressure in the discharge tube the discharge in them takes place at the same potential.
Reason : The discharge depends only on the pressure of discharge tube and not on the ionisation potential of gas.
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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. |
A stream of electrons is projected horizontally to the right. A straight conductor carrying a current is supported parallel to electron stream and above it. If the current in the conductor is from left to right then what will be the effect on electron stream
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(a) The electron stream will be pulled upward |
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(b) The electron stream will be pulled downward |
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(c) The electron stream will be retarted |
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(d) The electron beam will be speeded up towards the right |
Match the List I with the List II from the combination shown. In the left side (List I) there are four different conditions and in the right side (List II), there are ratios of heat produced in each resistance for each condition :
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List I |
List II |
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(I) |
Two wires of same resistance are connected in series and same current is passed through them |
(A) |
1 : 2 |
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(II) |
Two wires of resistance R and 2R ohm are connected in series and same P.D. is applied across them |
(B) |
4 : 1 |
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(III) |
Two wires of same resistance are connected in parallel and same current is flowing through them |
(C) |
1 : 1 |
|
(IV) |
Two wires of resistances in the ratio 1 : 2 are connected in parallel and same P.D. is applied across them |
(D) |
2 : 1 |
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(a) I – B; II – A; III – C; IV - D |
(b) I – C; II – D; III – C; IV - D |
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(c) I – B; II – D; III – A; IV - C |
(d) I – A; II – B; III – D; IV - C |
No bias is applied to a P-N junction, then the current
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(a) Is zero because the number of charge carriers flowing on both sides is same |
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(b) Is zero because the charge carriers do not move |
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(c) Is non-zero |
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(d) None of these |
A 25 watt, 220 volt bulb and a 100 watt, 220 volt bulb are connected in parallel across a 220 volt line. Which bulb will glow more brightly
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(a) 25 watt bulb |
(b) 100 watt bulb |
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(c) Both will have same brightness |
(d) First 25 watt then 100 watt |