IIT-JEE 2007 · Paper 1 · Physics Q17

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PhysicsSingle correct+4 / -1Question 17 of 66

Passage

Paragraph for Question Nos. 17 to 19

A fixed thermally conducting cylinder has a radius $R$ and height $L_0$ . The cylinder is open at its bottom and has a small hole at its top. A piston of mass $M$ is held at a distance $L$ from the top surface, as shown in the figure. The atmospheric pressure is $P_0$ .

(Figure: a vertical cylinder of radius R, closed at the top except for a small hole, open at the bottom; a piston of mass M inside at distance L below the top.)

(The paragraph is not printed in the official archive copy (which reproduces only the questions with their answers); its text is restored from the JEE 2007 question paper.)

The piston is now pulled out slowly and held at a distance $2L$ from the top. The pressure in the cylinder between its top and the piston will then be

P_0

\dfrac{P_0}2

\dfrac{P_0}2+\dfrac{Mg}{\pi R^2}

\dfrac{P_0}2-\dfrac{Mg}{\pi R^2}

Answer and worked solution

Official answer: A

Open hole. The space between the top and the piston is connected to the atmosphere through the hole, so when the piston is moved slowly its pressure stays $P_0$ .

(A)

Topics:Pressure and Pascal's law

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IIT-JEE 2007 · Paper 1, Physics question 17