156. A sonometer wire having a length of 50 cm is vibrating in the fundamental made with a frequency of 100 Hz. Which of the following is the type of propagating wave and its speed ?

1. 1. Longitudinal, 50 m / s

   
   
   

   2. Transverse, 50 m / s

   
   
   

   3. Longitudinal, 100 m / s

   
   
   

   4. Transverse, 100 m / s

   
   
   

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   NA

   Correct Option: D

   NA

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157. Sound moves with higher velocity if

1. 1. Pressure of the medium is decreased

   
   
   

   2. Temperature of the medium is increased

   
   
   

   3. Humidity of the medium is decreased

   
   
   

   4. Both (b) and (c)

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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158. An accelerated electron would produce

1. 1. ∝ - rays

   
   
   

   2. y - rays

   
   
   

   3. β - rays

   
   
   

   4. E.M. rays

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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159. Which of the following is the infrared wavelength?

1. 1. 10^-4 cm

   
   
   

   2. 10^-5 cm

   
   
   

   3. 10^-6 cm

   
   
   

   4. 10^-7 cm

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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160. If V_1, V₂ and V₃ are the velocities of sound in steel, water and vacuum respectively, which one of the following relations is correct ?

1. 1. V₁ < V₂ < V₃

   
   
   

   2. V₁ < V₂ + V₃

   
   
   

   3. V₁ = V₂ = V₃

   
   
   

   4. V₁ . V₂ . V₃ = 0

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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