- Aits length
- Barea of its cross-section
- ✓its substance
- Dits shape
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Assertion : The number of electrons in a P-type silicon semiconductor is less than the number of electrons in a pure silicon semiconductor at room temperature.
Reason : It is due to law of mass action.
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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. |
X-rays and gamma rays are both electromagnetic waves. Which of the following statements is true
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(a) In general X-rays have larger wavelength than of gamma rays |
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(b) X-rays have smaller wavelength than that of gamma rays |
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(c) Gamma rays have smaller frequency than that of X-rays |
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(d) Wavelength and frequency of X-rays are both larger than that of gamma rays |
A charged ball B hangs from a silk thread S, which makes an angle θ with a large charged conducting sheet P, as shown in the figure. The surface charge density σ of the sheet is proportional to

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(a) sin θ |
(b) tan θ |
(c) cos θ |
(c) cos θ |
The patient is asked to drink
for examining the stomach by X-rays because X-rays are
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(a) Reflected by heavy atoms |
(b) Refracted by heavy atoms |
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(c) Less absorbed by heavy atoms |
(d) More absorbed by heavy atoms |