- AHelium
- BXenon
- CNeon
- DArgon
Explanation:
Pierre Janssen discovered the gaseous nature of the solar chromosphere and with some justification the element helium.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Assertion : The air bubble shines in water.
Reason : Air bubble in water shines due to refraction of light
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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. |
When a charged particle enters a uniform magnetic field its kinetic energy
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(a) Remains constant |
(b) Increases |
(c) Decreases |
(d) Becomes zero |
The sun revolves around the galaxy with a speed of 250 km/sec and it's radius is 3 × 104 light year. The mass of the milky way is
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(a) 3 × 1040 kg |
(b) 3 × 1041 kg |
(c) 5 × 1040 kg |
(d) 6 × 1041 kg |
The half life of radioactive Radon is 3.8 days. The time at the end of which 1/20 th of the Radon sample will remain undecayed is (Given ![]()
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(a) 3.8 days |
(b) 16.5 days |
(c) 33 days |
(d) 76 days |