1)

Two light balls are suspended as shown in the figure. When the stream of air passes through  the space between them, the distance between the balls will

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A) remain same

B) increase

C) may increase or decrease, depending on spend of air

D) decrease

Answer:

Option D

Explanation:

 When a stream of air passes through the space between the balls, the pressure reduces between them as compared to the atmospheric pressure on either side. So, according to Bernoulli's theorem, the pressure energy should be constant and is compensated by the movement of balls toward each other. So, the distance between the balls will decrease.