An electron moves at right angle to a magnetic field of

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

201.

A coil having N turns carry a current as shown in the figure. The magnetic field intensity at point  P 

  • μ0NiR22R2+x232

  • μ0Ni2R

  • μ0 NiR2R+x2

  • Zero


Advertisement

202.

An electron moves at right angle to a magnetic field of 1.5×10-2 T with a speed of 6 x 107 m / s. If the specific charge of the electron is 1.7x 1011 C/ kg. The radius of the circular path will be

  • 2.9 cm

  • 3.9 cm

  • 2.35 cm

  • 2 cm


C.

2.35 cm

The formula for radius of circular path is

r=m νe B= νemBSuppose the cut off wavelength isrepresented by λoso, h cλo  =work function=Woh cλo  =4.2 × 1.6 × 10-19λo =6.6 × 10-34 × 3 × 1084.2 × 1.6 ×  10-19 =2946 × 10-102950 Ao


Advertisement
203.

If a charge particle enters perpendicularly in the uniform magnetic field, then:

  • energy and momentum both remains constant

  • energy remains constant but momentum changes

  • both energy and momentum changes

  • energy changes but momentum remains constant 


204.

A coil in the shape of an equilateral triangle of side l is suspended between the pole pieces of a permanent magnet such that B is in plane of the coil. If due to current i in the triangle a torque T acts on it, the side l of the triangle is


Advertisement
205.

An electron moves in a circular orbit with a uniform speed v. It produces a magnetic field B at the centre of the circle. The radius of the circle is proportional, to

  • B/v

  • v/B

  • √v/B

  • √B/v


206.

In a mass spectrometer used for measuring the masses of ions, the ions are initially accelerated by an electric potential V and then made to describe semicircular paths of radius R using a magnetic field B. If V and B are kept constant the ratio charge on the ionmass of the ion will be proportional to

  • 1R

  • 1R2

  • R2

  • R


207.

The north pole of a long horizontal bar magnet is being brought closer to a vertical conducting plane along the perpendicular direction. The direction of the induced current in the conducting plane will be

  • horizontal

  • vertical

  • clockwise

  • Anticlockwise


208.

An electric current passes through a long straight copper wire. At a distance 5 cm from the straight wire, the magnetic field is B. The magnetic field at 20 cm from the straight wire would be

  • B6

  • B4

  • B3

  • B2


Advertisement
209.

An electron of mass m and charge q is travelling with a speed v along a circular path of radius r at right angles to a uniform magnetic field B. If speed of the electron is doubled and the magnetic field is halved, then resulting path would have a radius of

  • r4

  • r2

  • 2r

  • 4r


210.

A galvanometer acting as a voltmeter should have

  • low resistance in series with its coil

  • low resistance in parallel with its coil

  • high resistance in series with its coil

  • high resistance in parallel with its coil


Advertisement