MCQ
With the decrease in the wave length of the incident radiation the velocity of the photoelectrons emitted from a given metal
- ARemains same
- BIncreases
- CDecreases
- DIncreases first and then decreases
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A magnetic needle is made to vibrate in uniform field H, then its time period is T. If it vibrates in the field of intensity 4H, its time period will be
| (a) 2T | (b) T/2 | (c) 2/T | (c) 2/T |
The core of a transformer is laminated so that
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(a) Ratio of voltage in the primary and secondary may be increased |
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(b) Rusting of the core may be stopped |
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(c) Energy losses due to eddy currents may be reduced |
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(d) Change in flux is increased |