CBSE Class 10 Science Magnetic Effects of Electric Current Assignment Set A

True/False

Question. An electron and a proton move in a uniform magnetic field with same speed perpendicular to the magnetic field. They experience forces in opposite directions differing by a factor of 1840.
Answer : False

Question. The direction of force on a current carrying conductor placed in a magnetic field can be reversed by reversing the direction of current flowing in the conductor.
Answer : True

Question. The field lines inside the infinite solenoid are in the form of parallel straight lines.
Answer : True

Question. The pattern of the magnetic field around a conductor due to an electric current flowing through it depends on the shape of the conductor.
Answer : True

Question. The magnitude of induced current can be increased by decreasing the speed of rotation of coil.
Answer : False

Question. The electrician must always follow the correct colour code while wiring the household circuits.
Answer : True

Question. The field at the centre of a long circular coil carrying current will be parallel straight lines.
Answer : True

Question. It is standard practice to connect fuse wire in the neutral wire of the household wiring.
Answer : False

Question. We use the ‘right hand thumb rule’ for finding the direction of the magnetic field due to both a (current carrying) straight wire as well as a circular coil.
Answer : True

Question. Every household circuit must have proper earth wire installed in it.
Answer : True

Assertion and Reason

DIRECTION : In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
(e) Both Assertion and Reason are false.

Question. Assertion : A neutral body may experience a net nonzero magnetic force.
Reason : The net charge on a current carrying wire is zero, but it can experience a force in a magnetic field.
Answer : A

Question. Assertion : When number of turns in a coil is doubled coefficient of self-inductance of the coil becomes 4 times.
Reason : This is because L ? N2 .
Answer : B

Question. Assertion : A compass needle is placed near a current carrying wire. The deflection of the compass needle decreases when the compass needle is displaced away from the wire.
Reason : Strength of a magnetic field decreases as one moves away from a current carrying conductor.
Answer : A

Question. Assertion : In Fleming’s Left Hand Rule, the direction of magnetic field, force and current are mutually perpendicular.
Reason : Fleming’s Left hand Rule is applied to measure the induced current.
Answer : C

Question. Assertion : A small coil carrying current, in equilibrium, is perpendicular to the direction of the uniform magnetic field.
Reason : Torque is maximum when plane of coil and direction of the magnetic field are parallel to each other.
Answer : B

Question. Assertion : On changing the direction of flow of current through a straight conductor, the direction of a magnetic field around the conductor is reversed.
Reason : The direction of magnetic field around a conductor can be given in accordance with left hand thumb rule.
Answer : C

Question. Assertion : an induced current has a direction such that the magnetic flux that induces the current.
Reason : Above statement is in accordance with conservation of energy.
Answer : A

Question. Assertion : A proton moves horizontally towards a vertical long conductor having an upward electric current. It will deflect vertically downward.
Reason : Seeing the proton and the conductor from the side of the proton, the magnetic field at the site of the proton will be towards right. Hence the force Fv = qnv #Bv will deflect the proton vertically downward.
Answer : A

Question. Assertion : No net force acts on a rectangular coil carrying a steady current when suspended freely in a uniform magnetic field.
Reason : Force on coil in magnetic field is always nonzero.
Answer : C

Question. Assertion : The strength of the magnetic field produced at the centre of a current carrying circular coil increases on increasing the radius of the circular coil.
Reason : Magnetic field strength is inversely proportional to the radius of the circular coil.
Answer : D

Question. Assertion : Lenz’s law violates the principle of conservation of energy.
Reason : Induced e.m.f. always opposes the change in magnetic flux responsible for its production.
Answer : A

Question. Assertion : Alternating Current is used in household supply.
Reason : AC electric power can be transmitted over long distance without much loss of energy.
Answer : A

Question. Assertion : The strength of the magnetic field produced at the centre of a current carrying circular coil increases on increasing the number of turns of the circular coil.
Reason : Magnetic field strength is directly proportional to the number of turns of the circular coil.
Answer : A

Answer : A-r, B-q, C-r, D-p

Question. In column I, the position of small current carrying loops have been shown and in column II information related to force experienced by coil is given. Match the entries of column I with the entries of column II.(Assume solenoid radius to be small as compared to its length)

Answer : (c) A-r, B-p, C-p, D-s

Question. In magnetic field, for a charged particle, match the entries of column I with the entries of column II.

Answer : (a) A-p, B-r, C-s, -D-s

Question. Two wires each carrying a steady current I are shown in four configurations in Column I. Some of the resulting effects are described in Column II. Match the statements in Column I with the statements in column II.

Answer : (c) A-q, r B-p, C-q, r, D-q, s

Question. Column I contains some features of AC supply in India and Column II contains their relevant values/details. Match Columns I and II.