- ✓by giving it extra electrons
- Bby removing some electrons from it
- Cby giving it some protons
- Dby removing some neutrons from it
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The magnifying power of a microscope with an objective of 5 mm focal length is 400. The length of its tube is 20 cm. Then the focal length of the eye-piece is
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(a) 200 cm |
(b) 160 cm |
(c) 2.5 cm |
(d) 0.1 cm |
The radius of a soap bubble whose potential is 16V is doubled. The new potential of the bubble will be
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(a) 2V |
(b) 4V |
(c) 8V |
(d) 16V |
Four charges +Q, -Q, +Q, -Q are placed at the corners of a square taken in order. At the centre of the square
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(a) E = 0, V = 0 |
(b) E = 0, V ≠ 0 |
(c) E ≠ 0, V = 0 |
(d) E = 0, V ≠ 0 |
Assertion : Self-inductance is called the inertia of electricity.
Reason : Self-inductance is the phenomenon, according to which an opposing induced e.m.f. is produced in a coil as a result of change in current or magnetic flux linked in the coil.
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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 core of a transformer is laminated to reduce energy losses due to
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(a) Eddy currents |
(b) Hysteresis |
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(c) Resistance in winding |
(d) None of these |
A proton and an electron both moving with the same velocity v enter into a region of magnetic field directed perpendicular to the velocity of the particles. They will now move in circular orbits such that
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(a) Their time periods will be same |
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(b) The time period for proton will be higher |
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(c) The time period for electron will be higher |
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(d) Their orbital radii will be same |
The dependence of binding energy per nucleon,
on the mass number, A, is represented by
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(a)
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(b)
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(C)
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(d)
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