## Sunday, October 11, 2009

### IIT JEE Physics Final Revision Set 18

1. T1 is the time period of simple pendulum. The point of suspension moves vertically upwards according to y =kt², where k = 1 m/s². New time period is T2, then T1²/T2² = ? ( g = 10 m/s²)

(A) 4/5 (B) 6/5
(C) 5/6 (D) 1

2.Which of the following does not have the same dimension?
(A) Electric flux, Electric field, Electric dipole moment
(B) Pressure, stress, Young’s modulus
(C) Electromotive force, Potential difference, Electric voltage.
(D) Heat, Potential energy, Work done

3. A capacitor (C = 4.0 µF) is connected through a resistor (R = 2.5 MΩ) across a battery of negligible internal resistance of voltage 12 volts. The time after which the potential difference across the capacitor becomes three
times to that of resistor is (ln 2 = 0.693)

(A) 13.86 sec. (B) 6.48 sec.
(C) 3.24 sec. (D) 20.52 sec.

4. A photon of energy 10.2 eV collides inelastically with a Hydrogen atom in ground state. After a certain time
interval of few micro seconds another photon of energy 15.0 eV collides inelastically with the same hydrogen
atom, then the observation made by a suitable detector is
(A) 1 photon with energy 10.2 eV and an electron with energy 1.4 eV
(B) 2 photon with energy 10.2 eV
(C) 2 photon with energy 1.4 eV
(D) one photon with energy 3.4 eV and 1 electron with energy 1.4 eV

5. In a resonance tube with tuning fork of frequency 512Hz, first resonance occurs at water level equal to
30.3 cm and second resonance occurs at 63.7 cm. The maximum possible error in the speed of sound is
(A) 51.2 cm/s (B) 102.4 cm/s
(C) 204.8 cm/s (D) 153.6 cm/s

Source: 2005 JEE screening