- AExpansion of the universe
- BThe Uncertainty Principle
- CBlack holes
- DSuperconductivity
Explanation:
Red shift is the increase in wavelength of light observed due to Doppler Effect of light, observed when objects recede from each other.
The red shift as observed in distant galaxies suggests that the galaxies are moving away from us and from each other. This tells that the universe is expanding.
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Assertion : The electromagnetic waves of shorter wavelength can travel longer distances on earth's surface than those of longer wavelengths.
Reason : Shorter the wavelength, the larger is the velocity of wave propagation.
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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. |
The characteristic X-ray radiation is emitted, when
| (a) The electrons are accelerated to a fixed energy |
| (b) The source of electrons emits a monoenergetic beam |
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(c) The bombarding electrons knock out electrons from the inner shell of the target atoms and one of the outer electrons falls into this vacancy |
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(d) The valence electrons in the target atoms are removed as a result of the collision |
A nucleus decays by
emission followed by a gamma emission. If the atomic and mass numbers of the parent nucleus are Z and A respectively, the corresponding numbers for the daughter nucleus are respectively.
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(a) Z - 1 and A - 1 |
(b) Z + 1 and A |
(c) Z - 1 and A |
(d) Z + 1 and A - 1 |
Name of the India's first nuclear reactor is
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(a) RAMBHA |
(b) MENAKA |
(c) URVASI |
(d) APSARA |
Eels are able to generate current with biological cells called electroplaques. The electroplaques in an eel are arranged in 100 rows, each row stretching horizontally along the body of the fish containing 5000 electroplaques. The arrangement is suggestively shown below. Each electroplaques has an emf of 0.15 V and internal resistance of 0.25 W

The water surrounding the eel completes a circuit between the head and its tail. If the water surrounding it has a resistance of 500 W, the current an eel can produce in water is about
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(a) 1.5 A |
(b) 3.0 A |
(c) 15 A |
(d) 30 A |
The two metallic plates of radius r are placed at a distance d apart and its capacity is C. If a plate of radius r/2 and thickness d of dielectric constant 6 is placed between the plates of the condenser, then its capacity will be
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(a) 7C/2 |
(b) 3C/7 |
(c) 7C/3 |
(d) 9C/4 |