NCERT Class 11 Physics Gk Questions & Answers

NCERT Class 11 Physics Gk Questions & Answers NCERT Class 11 Physics QUESTIONS

NCERT Class 11 Physics Gk Questions & Answers

11 Which of the following is wrong? Resistivity of a conductor is
A independent of temperature.
B inversely proportional to temperature.
C independent of dimensions of conductor.
D less than resistivity of a semiconductor.

12 What does Newton’s third law states for the conservative forces?
A The rate of change of momentum is equal to the force applied
B For every reaction, there is an opposite reaction
C The body tends to be rotated if the force is applied tangentially
D The body is rest until a force is applied

Answer: For every reaction, there is an opposite reaction
13 The conservative frictional force always acts ____________ to the surface of the application of the friction.
A Tangential
B Parallel
C Perpendicular
D Normal

14 Two cells of emf’s approximately 5 V and 10 V are to be accurately compared using a potentiometer of length 400 cm.
A The battery that runs the potentiometer should have voltage of 8 V.
B The battery of potentiometer can have a voltage of 15 V and R adjusted so that the potential drop across the wire slightly exceeds 10 V.
C The first portion of 50 cm of wire itself should have a potential drop of 10 V.
D Potentiometer is usually used for comparing resistances and not voltages.

Answer: The battery of potentiometer can have a voltage of 15 V and R adjusted so that the potential drop across the wire slightly exceeds 10 V.
15 A resistance R is to be measured using a meter bridge. Student chooses the standard resistance S to be 100 Ω He finds the null point at l1 = 2.9 cm. He is told to attempt to improve the accuracy. Which of the following is a useful way?
A He should measure l1 more accurately.
B He should change Sto 1000 Ω and repeat the experiment.
C He should change S to 3 Ω and repeat the experiment.
D He should give up hope of a more accurate measurement with a meter bridge.

Answer: He should change S to 3 Ω and repeat the experiment.
16 A cubical region of space is filled with some uniform electric and magnetic fields. An electron enters the cube across one of its faces with velocity v and a positron enters via opposite face with velocity -v. At this instant,
A the electric forces on both the particles cause identical accelerations.
B the magnetic forces on both the particles cause equal accelerations.
C Only electron gains or looses energy.
D the motion of the centre of mass (CM) is determined by E alone.

Answer: the magnetic forces on both the particles cause equal accelerations.
17 A circular coil of radius 4 cm and of 20 turns carries a current of 3 amperes. It is placed in a magnetic field of intensity of 0.5 weber/m². The magnetic dipole moment of the coil is
A 0.15 ampere-m²
B 0.3 ampere-m²
C 0.45 ampere-m²
D 0.6 ampere-m²

18 In a cyclotron, a charged particle
A undergoes acceleration all the time.
B speeds up between the dees because of the magnetic field.
C speeds up in a dee.
D slows down within a dee and speeds up between dees.

Answer: undergoes acceleration all the time.
19 An electron is projected with uniform velocity along the axis of a current carrying long solenoid. Which of the following is true?
A The electron will be accelerated along the axis.
B The electron path will be circular about the axis.
C The electron will experience a force at 45° to the axis and hence execute a helical path.
D The electron will continue to move with uniform velocity along the axis of the solenoid

Answer: The electron will continue to move with uniform velocity along the axis of the solenoid
20 A current carrying circular loop of radius R is placed in the x-y plane with centre at the origin. Half of the loop with x > 0 is now bent so that it now lies in the y – z plane.
A The magnitude of magnetic moment now diminishes.
B The magnetic moment does not change.
C The magnitude of B at (0.0.z), z» R increases.
D The magnitude of B at (0, 0, z), z » R is unchanged.

Answer: The magnitude of magnetic moment now diminishes.