JEE Main 2019 (Online) 10th January Evening Slot | Magnetics Question 199 | Physics

JEE Main 2019 (Online) 10th January Evening Slot

MCQ (Single Correct Answer)

-1

At some location on earth the horizontal component of earth’s magnetic field is 18 × 10^–6 T. At this location, magnetic needle of length 0.12 m and pole strength 1.8 Am is suspended from its mid-point using a thread, it makes 45^o angle with horizontal in equilibrium. To keep this needle horizontal, the vertical force that should be applied at one of its ends is -

3.6 $$ \times $$ 10^$$-$$5 N

1.8 $$ \times $$ 10^$$-$$5 N

1.3 $$ \times $$ 10^$$-$$5 N

6.5 $$ \times $$ 10^$$-$$5 N

JEE Main 2019 (Online) 10th January Evening Slot

MCQ (Single Correct Answer)

-1

A hoop and a solid cylinder of same mass and radius are made of a permanent magnetic material with their magnetic moment parallel to their respective axes. But the magnetic moment of hoop is twice of solid cylinder. They are placed in a uniform magnetic field in such a manner that their magnetic moments make a small angle with the field. If the oscillation periods of hoop and cylinder are T_h and T_c respectively, then -

T_h = 1.5 T_c

T_h = T_c

T_h = 2T_c

T_h = 0.5 T_c

JEE Main 2019 (Online) 10th January Morning Slot

MCQ (Single Correct Answer)

-1

A magnet of total magnetic moment 10^-2$${\widehat i}$$A-m² is placed in a time varying magnetic field, B$${\widehat i}$$ (co where B = 1 Tesla and $$\omega $$ = 0.125 rad/s. The work done for reversing the direction of the magnetic moment at t = 1 second, is -

0.014 J

0.028 J

0.01 J

0.007 J

JEE Main 2019 (Online) 10th January Morning Slot

MCQ (Single Correct Answer)

-1

A solid metal cube of edge length 2 cm is moving in a positive y-direction at a constant speed of 6 m/s. There is a uniform magnetic field of 0.1 T in the positive z-direction. The potential difference between the two faces of the cube perpendicular to the x-axis, is -

2mV

12 mV

6 mV

1 mV

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