IIT JEE Physics Final Revision Set 20

1. An open organ pipe resonated with frequency ‘f1’ and 2nd harmonic. Now one end is closed and the frequency is slowly increased then it resonates with frequency f2 and nth harmonic then

(a) n = 3, f2 = (3/4)f1
(b) n = 5, f2 = (3/4)f1
(c) n = 3, f2 = (5/4)f1
(d) n = 5, f2 = (5/4)f1

2. Temperature of a gas is 20°C and pressure is changed from 1.01×10⁵ Pa to 1.165×10⁵ Pa . If volume is decreased isothermally by 10%. Bulk modulus of gas is
(A) 1.55× 10⁵ (B) 0.155× 10⁵
(C) 1.4× 10⁵ (D) 1.01×10⁵

3. A galvanometer with resistance 100Ω is converted to ammeter with a resistance of 0.1Ω. The galvanometer shows full scale deflection with a current of 100 µA. Then the minimum current in the circuit for full scale deflection of galvanometer will be

(A) 100.1mA (B) 10.01mA
(C) 1.001mA (D) 0.1001mA

4. One calorie is defined as the heat required to raise the temperature of 1 gm of water by 1°C in a certain interval of temperature and at certain pressure. The temperature interval and pressure is

(A) 13.5° C to 14.5° C & 76 mm of Hg (B) 6.5° C to 7.5° C & 76 mm of Hg
(C) 14.5° C to 15.5° C & 760 mm of Hg (D) 98.5° C to 99.5° C & 760 mm of Hg

5. If a star converts all of its Helium into oxygen nucleus, find the amount of energy released per nucleus of
oxygen. He = 4.0026 amu, O = 15.9994 amu
(A) 7.26 MeV (B) 7 MeV
(C) 10.24 MeV (D) 5.12 MeV

Source: 2005 JEE screening