A convex lens forms a real image of an object for its two different positions on a screen. If height of the image in both the cases be 8 cm and 2 cm, then height of the object is
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(a) 16 cm |
(b) 8 cm |
(c) 4 cm |
(d) 2 cm |
(c) 4 cm
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A uniform but time-varying magnetic field B(t) exists in a circular region of radius a and is directed into the plane of the paper, as shown. The magnitude of the induced electric field at point P at a distance r from the centre of the circular region
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(a) Is zero |
(b) Decreases as |
(c) Increases as r |
(d) Decreases as |
Which of the following statements is not true
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(a) The resistance of intrinsic semiconductors decrease with increase of temperature |
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(b) Doping pure Si with trivalent impurities give P-type semiconductors |
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(c) The majority carriers in N-type semiconductors are holes |
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(d) A PN-junction can act as a semiconductor diode |
A converging lens is used to form an image on a screen. When upper half of the lens is covered by an opaque screen
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(a) Half the image will disappear |
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(b) Complete image will be formed of same intensity |
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(c) Half image will be formed of same intensity |
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(d) Complete image will be formed of decreased intensity |
Assertion : The whole charge of a conductor cannot be transferred to another isolated conductor.
Reason : The total transfer of charge from one to another is not possible.
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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 particles which can be added to the nucleus of an atom without changing its chemical properties are called
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(a) Electrons |
(b) Protons |
(c) Neutrons |
(d) None of the above |
Assertion : No interference pattern is detected when two coherent sources are infinitely close to each other.
Reason : The fringe width is inversely proportional to the distance between the two slits.
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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. |
