# MCQs / Compilation of Physics Problems Part 7 MCQs / Compilation of Physics Problems
PRACTICE TEST IN PHYSICS SET 7

1. A current of 5 A passes along a wire of length 1.0 m. the wire is at right angles to a magnetic field of flux density of 0.15 T. The force acting on the wire is...
A. 0
B. 0.03 N
C. 0.75 N
D. 33 N

2. The end product of most radioactive decay series is usually some form of
A. carbon
B. helium
C. hydrogen

3. The cause of surface tension is...
B. cohesive forces
C. external forces
D. gravitational force

4. The unit 'poise' is...
A. dyne.sec/cm2
B. dyne.cm/sec2
C. newton.sec/m2
D. dyne.sec/cm

5. Emission line spectrum will be obtained from...
A. candle flame
B. sodium lamp
C. Sun
D. white hot filament of an electric bulb

6. A hollow insulated brass sphere is positively charged. The electric potential inside the sphere is...
A. zero
B. greater than the potential at the surface
C. smaller than the potential at the surface
D. the same as that on the surface

7. The linear momentum of a body is P = a + (bt2/2). The force acting on the body is...
A. a + (bt/2)
B. a + bt
C. bt/2
D. bt

8. The weight of a body on the surface of earth is 100 N. Its weight at a depth half way to the centre of earth will be...
A. 50 N
B. 100 N
C. 25 N
D. 125 N

9. Two wires C and D of the length in the ratio 2 : 3, diameter in the ratio 2 : 3 and of the same material, are subjected to same force. Then the ratio of their extentions lc : ld is...
A. 3 : 2
B. 2 : 3
C. 4 : 9
D. 8 : 27

10. The potential energy of a harmonic oscillator is maximum when the displacement is equal to...
A. zero
B. 1/2 amplitude
C. amplitude
D. 1/4 amplitude

11. When the forces acting on a body are in equilibrium, its...
A. velocity is zero
B. displacement is zero
C. acceleration is zero
D. momentum is zero

12. An object at rest may possess...
A. velocity
B. momentum
C. kinetic energy
D. potential energy

13. A nonconservative force does not give rise to...
A. thermal energy
B. kinetic energy
C. light energy
D. potential energy

14. Atoms forming a molecule attain the arrangement in which they obtain...
A. zero potential energy
B. minimum potential energy
C. maximum potential energy
D. none of the above

15. Bulk modulus of a liquid is...
A. higher than that for a solid
B. higher than that for a gas
C. lower than that for a gas
D. zero

16. The CGS unit of coefficient of viscosity is...
A. dyne.second/cm2
B. newton.second/cm2
C. dyne.(second)2/cm2
D. newton.second/cm

17. The volume of a gas sample is directly proportional to its...
A. Fahrenheit temperature
B. Celsius temperature
C. Kelvin temperature
D. pressure

18. The approximate relationship between the coefficient of linear expansion(α) and the coefficient of cubical expansion(γ) is...
A. γ = α2
B. γ = α3
C. α = 3 γ
D. γ = 3 α

19. When capacitors are in parallel...
A. they are all at the same potential
B. they are at different potentials
C. their capacitances are equal
D. the equivalent capacitance is zero

20. The earth's magnetic field at sea level is...
A. 3 x 10-9 T
B. 3 x 109 T
C. 3 x 10-5 T
D. 3 x 105 T

21. Monoatomic gases give...
A. line spectra
B. band spectra
C. continuous spectra
D. line and band spectra

22. The centre of mass of a rigid body...
A. lies inside the body
B. lies outside the body
C. can be inside or outside of the body
D. may not exist

23. If 'l' is the length of a simple pendulum and 'T' its period, then 'g' is given by...
A. (4π2l)/T2
B. 2π/(√ l/t)
C. 2πl/t
D. (4πl2)/t2

24. The rate at which an object radiates electromagnetic energy does not depend on its...
A. surface area
B. mass
C. temperature

25. Which of the following is neither a basic physical law nor derivable from one?
A. Coulomb's law
B. Ohm's law
C. Kirchhoff's first law
D. Kirchhoff's second law

26. The power dissipated as heat in an a.c. circuit depends on its...
A. resistance
B. inductive reactance
C. capacitive reactance
D. impedance

27. Impedance is a maximum at resonance in...
A. a series RLC circuit
B. a parallel RLC circuit
C. all RLC circuits
D. no RLC circuit

28. Red shift indicates...
A. recession of star
B. approaching movement of star
C. that red light changes to violet
D. that violet light changes to red

29. The penetration power of beta particles is 1. Then the relative penetration power of gamma rays is...
A. 1
B. 100
C.  1/1000
D.  1000

30. In a common-base circuit the current gain is...
A. 0
B. 1
C. greater than 1
D. smaller than 1