MCQ
Polarisation of light was first successfully explained by:
- ACorpuscular theory
- BHuygens' wave theory
- CElectromagnetic wave theory
- DPlanck's theory
Explanation:
Electromagnetic wave theory explains light as being composed of electric field vibrating in planes.
Polarisation of light refers to vibrating electric field in a particular plane.
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A 50 turns circular coil has a radius of 3 cm, it is kept in a magnetic field acting normal to the area of the coil. The magnetic field B increased from 0.10 tesla to 0.35 tesla in 2 milliseconds. The average induced e.m.f. in the coil is
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(a) 1.77 volts |
(b) 17.7 volts |
(c) 177 volts |
(d) 0.177 volts |
When light rays from the sun fall on a convex lens along a direction parallel to its axis
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(a) Focal length for all colours is the same |
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(b) Focal length for violet colour is the shortest |
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(c) Focal length for yellow colour is the longest |
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(d) Focal length for red colour is the shortest |
Assertion : If different gases are filled turn by turn at the same pressure in the discharge tube the discharge in them takes place at the same potential.
Reason : The discharge depends only on the pressure of discharge tube and not on the ionisation potential of gas.
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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 reading of a high resistance voltmeter when a cell is connected across it is 2.2 V. When the terminals of the cell are also connected to a resistance of 5Ω the voltmeter reading drops to 1.8 V. Find the internal resistance of the cell
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(a) 1.2 Ω |
(b) 1.3 Ω |
(c) 1.1 Ω |
(d) 1.4 Ω |
A current flows in a conductor from east to west. The direction of the magnetic field at a points above the conductor is .....
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(a) Towards north |
(b) Towards south |
(c) Towards east |
(d) Towards west |
The electron in a hydrogen atom makes a transition from an excited state to the ground state. Which of the following statements is true
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(a) Its kinetic energy increases and its potential and total energies decrease |
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(b) Its kinetic energy decreases, potential energy increases and its total energy remains the same |
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(c) Its kinetic and total energies decrease and its potential energy increases |
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(d) Its kinetic, potential and total energies decreases |