76. Solar energy is due to

1. 1. fusion reaction

   
   
   

   2. fission reaction

   
   
   

   3. combustion reaction

   
   
   

   4. chemical reaction

   
   
   

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1. View Hint View Answer Discuss in Forum

   Fusion reaction.

   Correct Option: A

   Fusion reaction.

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77. The energy equivalent of one atomic mass unit is

1. 1. 1.6 × 10^–19 J

   
   
   

   2. 6.02 × 10²³ J

   
   
   

   3. 931 MeV

   
   
   

   4. 9.31 MeV

   
   
   

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1. View Hint View Answer Discuss in Forum

   1 a.m.u = 931 MeV

   Correct Option: C

   1 a.m.u = 931 MeV

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78. An electron with (rest mass m₀) moves with a speed of 0.8 c. Its mass when it moves with this speed is

1. 1. m₀

   
   
   

   2. m0

      6

   
   
   

   3. 5m0

      3

   
   
   

   4. 3m0

      5

   
   
   

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1. View Hint View Answer Discuss in Forum

   

   Correct Option: C

   

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79. If the nuclear force between two protons, two neutrons and between proton and neutron is denoted by F_pp, F_nn and F_pn respectively, then

1. 1. F_pp ≈ F_nn ≈ F_pn

   
   
   

   2. F_pp + F_nn and F_pp =; F_nn

   
   
   

   3. F_pp= F_nn = F_pn

   
   
   

   4. F_pp ≠ F_nn ≠ F_pn

   
   
   

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1. View Hint View Answer Discuss in Forum

   Nuclear force is not the same between any two nucleons.

   Correct Option: D

   Nuclear force is not the same between any two nucleons.

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80. Which of the following statements is true for nuclear forces?

1. 1. they obey the inverse square law of distance

   
   
   

   2. they obey the inverse third power law of distance

   
   
   

   3. they are short range forces

   
   
   

   4. they are equal in strength to electromagnetic forces.

   
   
   

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1. View Hint View Answer Discuss in Forum

   Nuclear forces are short range attractive forces which balance the repulsive forces between the protons inside the nucleus.

   Correct Option: C

   Nuclear forces are short range attractive forces which balance the repulsive forces between the protons inside the nucleus.

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