71. Pick out the statement which is true

1. 1. The energy released per unit mass is more in fusion and that per atom in more in fission

   
   
   

   2. Both fission and fusion produce same amount of energy per atom as well as per unit mass

   
   
   

   3. The energy released per unit mass

   
   
   

   4. The energy released per atom is more in fusion then in fission

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

---

72. A photo sensitive material would emit electrons, if excited by photons beyond a threshold. To overcome the threshold, one would increase

1. 1. The voltage applied to the light source

   
   
   

   2. Intensity of light

   
   
   

   3. The wavelength of light

   
   
   

   4. The frequency of light

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

---

---

73. The cathode ray particles originate in a discharge tube from the

1. 1. Cathode

   
   
   

   2. Anode

   
   
   

   3. Source of high voltage

   
   
   

   4. Residual gas

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

---

74. Compton effect is associated with

1. 1. Positive rays

   
   
   

   2. β - rays

   
   
   

   3. y - rays

   
   
   

   4. X - rays

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

---

---

75. The fusion of hydrogen into helium is more likely to take place

1. 1. At high temperature and high pressure

   
   
   

   2. At high temperature and low pressure

   
   
   

   3. At low pressure and low temperature

   
   
   

   4. None of the above

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

---