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# IIT-JEE-Physics-Mains-2003

Mains
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NOTE : All these questions of ASKIITIANS Mains 2003 are based on the memory of the student who appeared in the examination. The publisher and the author do not take any responsibility for any sort of discrepancy whatsoever.

1.
N-divisions on the main scale of a vernier calipers coincide with N+1 divisions on the vernier scale. If each division on the main scale is of a units, determine the least count of the instrument.

2.
Characteristic X-rays of frequency 4.2 × 1018 Hz are produced when transitions from L shell to K shell take place in a certain target material. Use Mosley's law to determine the atomic number of the target material. Given Rydberg constant
R = 1.1 × 107 m-1

3.
In a resonance tube experiment to determine the speed of sound in air, a pipe of diameter 5 cm is used. The air column in pipe resonates with a tuning fork of frequency 480 Hz when the minimum length of the air column is 16 cm. Find the speed of sound in air at room temperature.

4.
An insulated box containing a monoatomic gas of molar mass M moving with a speed v0 is suddenly stopped. Find the increment in gas temperature as a result of stopping the box.

5.
A soap bubble is being blown at the end of a very narrow tube of radius b. Air (density r) moves with a velocity v inside the tube and comes to rest inside the bubble. The surface tension of the soap solution is T. After some time the bubble, having grown to a radius r, separates from the tube. Find the value of r. Assume that r > > b so that you can consider the air to be falling normally on the bubble's surface.

6.
Show by diagram, how can we use a rheostat as the potential divider.

7.
A radioactive element decays by b emission. A detector records n beta particles in 2 seconds and in next 2 seconds it records 0.75n beta particles. Find mean life correct to nearest whole number. Given In ½2½ = 0.6931, In ½3½ = 1.0986.