The structure of solid crystals is investigated by using
| (a) Cosmic rays | (b) X-rays | (c) Infrared radiations | (d) γ - rays |
The structure of solid crystals is investigated by using
| (a) Cosmic rays | (b) X-rays | (c) Infrared radiations | (d) γ - rays |
(b) X-rays
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Two resistance wires on joining in parallel the resultant resistance is . One of the wire breaks, the effective resistance is 2 ohms. The resistance of the broken wire is
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(a) |
(b) 2 ohm |
(c) |
(d) 3 ohm |
Kα wavelength emitted by an atom of atomic number Z = 11 is λ. Find the atomic number for an atom that emits Kα radiation with wavelength 4l
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(a) Z = 6 |
(b) Z = 4 |
(c) Z = 11 |
(d) Z = 44 |
Assertion : A person touching a high power line gets stuck with the line.
Reason : The current carrying wires attract the man towards it.
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(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. |
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(d) If the assertion and reason both are false. |
Magnifying power of a simple microscope is (when final image is formed at D = 25 cm from eye)
|
(a) |
(b) 1 + |
(c) |
(d) |
Half life of a radio-active substance is 20 minutes. The time between 20% and 80% decay will be
|
(a) 20 minutes |
(b) 40 minutes |
(c) 30 minutes |
(d) 25 minutes |