Explanation:
The Electromagnetic wave consists of the two mutually perpendicular electric and magnetic fields present in the medium and also both being perpendicular to the direction of propagation of the wave. The two fields are in same phase as they obtain their peaks at the same instant.
An electromagnetic wave consists of periodically oscillating electric and the magnetic vector in mutually perpendicular planes but vibrating in phase.
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Kirchoff’s I law and II law of current, proves the
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(a) Conservation of charge and energy |
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(b) Conservation of current and energy |
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(c) Conservation of mass and charge |
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(d) None of these |
For a transistor the parameter b = 99. The value of the parameter a is
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(a) 0.9 |
(b) 0.99 |
(c) 1 |
(d) 9 |
A conductor ABOCD moves along its bisector with a velocity of 1 m/s through a perpendicular magnetic field of 1 wb/m2, as shown in fig. If all the four sides are of 1m length each, then the induced emf between points A and D is
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(a) 0 |
(b) 1.41 volt |
(c) 0.71 volt |
(d) None of the above |
A nucleus with mass number 220 initially at rest emits an a-particle. If the Q value of the reaction is 5.5 MeV, calculate the kinetic energy of the a-particle
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(a) 4.4 MeV |
(b) 5.4 MeV |
(c) 5.6 MeV |
(d) 6.5 MeV |
An air capacitor of capacity C = 10μF is connected to a constant voltage battery of 12 V. Now the space between the plates is filled with a liquid of dielectric constant 5. The charge that flows now from battery to the capacitor is
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(a) 120 μC |
(b) 699 μC |
(c) 480 μC |
(d) 24 μC |
The number of turns in primary and secondary coils of a transformer are 100 and 20 respectively. If an alternating potential of 200 volt is applied to the primary, the induced potential in secondary will be
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(a) 10 V |
(b) 40 V |
(c) 1000 V |
(d) 20,000 V |
Assertion : A spark occur between the poles of a switch when the switch is opened.
Reason : Current flowing in the conductor produces magnetic field.
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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. |
Assertion : In the process of photoelectric emission, all the emitted photoelectrons have the same kinetic energy.
Reason : The photon transfers its whole energy to the electron of the atom in photoelectric effect.
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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 assertion is false but reason is true. |