A bar magnet of magnetic moment 104 J/T is free to rotate in a horizontal plane. The work done in rotating the magnet slowly from a direction parallel to a horizontal magnetic field of 4×10-5 T to a direction of 60 ° from the field will be
 

 


A rocket is fired upward from the earth surface such that it creates an acceleration of 19.6 m/s2. If after 5 s, its engine is switched off, the maximum height of the rocket from earth’s surface would be
 

1.  245 m
2.  490 m
3.  980 m
4.  735 m

Subtopic:  Distance & Displacement |
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A 60 kg weight s dragged on a horizontal surface by a rope through a distance of 2m. If coefficient of friction is μ=0.5, the angle of rope with surface is 60 ° and g =9.8 m/s2, then work done is
 
1.  294 J
2.  15 J
3.  588 J
4.  197 J

 

Subtopic:  Friction |
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A small uncharged metallic sphere is positioned exactly at a point midway between two equal and opposite point charges. If the sphere is slightly displaced towards the positive charge and released then
 

1.  it will oscillate about its original position
2.  it will move further towards the positive charge
3.  its electric potential energy will decrease and kinetic energy will increase
4.  its total energy remains constant but is non-zero

Subtopic:  Electric Potential Energy |
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A capacitor of capacitance 5μF is connected as shown in the figure. The internal resistance of the cell is 0.5 Ω. The amount of charge on the capacitor plate is 
1.  zero
2.  5μC
3.  10μC
4.  25 μC

 

Subtopic:  Capacitance |
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The resistance if a circular coil of 50 turns and 10 cm diameter is 5Ω. What must be the potential difference across that ends of the coil so as to nullify the earth’s magnetic field (H=0.314 gauss) at the centre of the coil? How should the coil be placed to achieve this result?
 

1.  0.5 V with plane of coil normal to the magnetic meridian
2.  0.5 V with plane of coil in the magnetic meridian
3.  0.25 V with plane of coil normal to the magnetic meridian
4.  0.25 V with plane of coil in the magnetic meridian

Subtopic:  Earth's Magnetism (OLD NCERT) |
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