Subject

Physics

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

51.

Assertion:  A diode lasers are used as optical sources in optical communication.

Reason: Diode lasers consume less energy.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


52.

Assertion: Diamond glitters brilliantly. 

Reason: Diamond does not absorb sunlight.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


53.

Assertion: The energy (E) and momentum (p) of a phoon are related by p = E/c.

Reason: the photon behaves like a particle.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


54.

Assertion:  The clouds in sky generally appear to be whitish. 

Reason:  Diffraction due to clouds is efficient in equal measure at all wavelengths.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


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55.

Assertion: Television signals are received through sky-wave propagation.

Reason: The ionosphere reflects electromagnetic waves of frequencies greater than a certain critical frequency

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


56.

Assertion: The logic gate NOT can be built using diode.

Reason: The output voltage and the input voltage of the diode have 180o phase difference.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


57.

Assertion:  The resolving power of a telescope is more if the diameter of the objective lens is more.

Reason:  Objective lens of large diameter collects more
light.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


58.

Assertion:  It is not possible to use  35Cl  as  the fuel for fusion energy.

Reason: The binding energy of  35Cl is too small.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


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59.

Assertion: The number of electrons in a p-type silicon  semiconductor is less than the number of electrons in a pure silicon semiconductor at room temperature.

Reason: It is due to law of mass action.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


A.

If both assertion and reason are true and reason is the correct explanation of assertion

The mass action law is a relation about the concentrations of free electrons and electron holes under thermal equilibrium. It states that, under thermal equilibrium. It states that, under thermal equilibrium, the product of free electron concentration ne and the free hole concentration  np  is equal a constant square of intrinsic carrier concentration ni. The  intrinsic carrier concentration is a function of temperature. 

According to law of mass action

          ni 2 = ne nh

In p-type semiconductor

        nh > ne


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60.

Assertion: In a common emitter transistor amplifier the input current is much less than the output current. 

Reason: The common emitter transistor amplifier has very high input impedance.

  • If both assertion and reason are true and reason is the correct explanation of assertion 

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false.


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