CBSE Class 11 Physics MCQs Set 7

Question. 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
Answer: C

Question. The end product of most radioactive decay series is usually some form of
A. carbon
B. helium
C. hydrogen
D. lead
Answer: D

Question. The cause of surface tension is...
A. adhesive forces
B. cohesive forces
C. external forces
D. gravitational force
Answer: B

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

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

Question. 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
Answer: D

Question. 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
Answer: D

Question. 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
Answer: A

Question. 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 extensions lc : ld is...
A. 3 : 2
B. 2 : 3
C. 4 : 9
D. 8 : 27
Answer: C

Question. 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
Answer: C

Question. 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
Answer: C

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

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

Question. 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
Answer: B

Question. 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
Answer: B

Question. 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
Answer: A

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

Question. 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
Answer: D

Question. 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
Answer: A

Question. 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
Answer: C

Question. Monoatomic gases give...
A. line spectra
B. band spectra
C. continuous spectra
D. line and band spectra
Answer: A

Question. 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
Answer: C

Question. 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
Answer: A

Question. The rate at which an object radiates electromagnetic energy does not depend on its...
A. surface area
B. mass
C. temperature
D. ability to absorb radiation
Answer: B

Question. 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
Answer: B

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

Question. 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
Answer: B

Question. 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
Answer: A

Question. 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
Answer: B

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