Multiple Choice Questions

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Assertion:   Microwave communication is peferred over optical communication. 

Reason: Microwaves provide large number of channels and bandwidth compared to optical signals.

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

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

  • if assertion is true and reason is false

  • if both assertion and reason are false statements


D.

if both assertion and reason are false statements

The quality of a communication system is determined by its information carrying capacity, The information carrying capacity is directly proportional to its bandwidth. The wider the bandwidth, the greater its information carrying capacity.

As the light frequencies used in optical fibre systems is much larger than the highest frequency microwave transmissions, so the bandwidth in case of optical communication  systems is much larger than that in microwave communications. The bandwidth of the optical fibre systems is quite suitable for the present day communication needs and also for the future. That's why optical communication is preferred over microwave communication.


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Assertion: Radioactive nuclei emit  β- particles.

Reason: Electrons exist inside the nucleus.

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

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

  • if assertion is true but reason is false

  • If both assertion and reason are false statements


Assertion: The resistivity of a semiconductor increases with temperature. 

Reason:  The atoms of a semiconductor vibrate with larger amplitude at higher temperatures thereby increasing its resistivity.

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

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

  • if assertion is true but reason is false

  • if both assertion and reason are false statements


Assertion: Bohr had to postulate that the electrons in stationary orbits around the nucleus do not radiate. 

Reason:  According to classical physics all moving electrons radiate.

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

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

  • if assertion is true but reason is false

  • if both assertion and reason are false statements


Assertion: The possibility of an electric bulb fusing is higher at the time of switching on and off.

Reason: Inductive effects produce a surge at the time of switch-off and switch-on.

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

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

  • if assertion is true but reason is false

  • if both assertion and reason are false statements


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Assertion:  The stars twinkle while the planets do not. 

Reason: The stars are much bigger in size than the planets.

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

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

  • if assertion is true but reason is false

  • if both assertion and reason are false statements


Assertion:  A beam of charged particles is employed in the treatment of cancer. 

Reason: Charged particles on passing through a material medium lose their energy by causing ionization of the atoms along their path.

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

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

  • if assertion is true but reason is false

  • if both assertion and reason are false statements


Assertion: Owls can move freely during night. 

Reason: They have large number of rods on their retina.

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

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

  • if assertion is true but reason is false

  • if both assertion and reason are false statements


Assertion: Neutrons penetrate matter more readily as compared to protons.

Reason: Neutrons are slightly more massive than protons.

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

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

  • if assertion is true but reason is false

  • if both assertion and reason are false statements


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Assertion: In high latitudes one sees colourful curtains of light hanging down from high altitudes. 

Reason: The high energy charged particles from the are deflected to polar regions by the magnetic field of the earth.

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

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

  • if assertion is true but reason is false

  • if both assertion and reason are false statements