Class XII Sub Physics U 3 Magnetic Effects of Current and Magnetism Date
MM 20 ALL QUESTIONS ARE MULTIPLE CHOICE TYPE CARRYING 1 MARK EACH Time 1hr
KNOWLEDGE BASED QUESTIONS
1. The face of the loop, in which the current appears to flow anticlockwise, acts as:
- (a) Magnetic North Pole
- (b) Magnetic South Pole
- (c) Half circle North and half circle South
- (d) None of these
2. Shunt resistance is
- (a) a small resistance connected in parallel with a galvanometer or a ammeter to protect it from strong currents
- (b) a high resistance used in series with a galvanometer to increase the potential difference
- (c) a very small resistance to be used in series with the galvanometer
- (d) a very high resistance to be used in parallel with the galvanometer
3. One Tesla is equal to
- (a) `10^{7}` Gauss
- (b) `10^{-4}` Gauss
- (c) `10^{4}` Gauss
- (d) `10^{8}` Gauss
4. The magnetic field due to Infinitely long current carrying conductor at a distance r from conductor depends upon distance r as
- (a) B ∝ r
- (b) B ∝ 1/r
- (c) B ∝ r 2
- (d) B ∝ 1/r2
5. The dimensions of magnetic field are
- (a) M`L^{2}` `T^{-2}`
- (b) M`L^{2}` `T^{-2}``A^{-1}`
- (c) M`L^{0}` `T^{-2}``A^{-1}`
- (d) None of these
6. For a point on the axis of a circular coil carrying current, magnetic field at the centre of the coil is
- (a) Minimum but non zero
- (b) zero
- (c) Maximum
- (d) Can’t be determined
7. Ampere’s circuital law is
- (a) ∮ ๐ฉ. ๐ ๐ = ๐๐ I
- (b) ∮ ๐ต. ๐๐ = I / ๐๐
- (c) ∮ ๐ต⃗ . ๐๐ = ๐0. I
- (d) ∮ ๐ต⃗ . ๐๐ ⃗⃗⃗ = I / ๐0
UNDERSTANDING BASED QUESTIONS
8. S.I. unit of magnetic pole strength is:- (a) Am
- (b) A`m^{-1}`
- (c) A`m^{-2}`
- (d) A`m^{2}`
9. The pole strength of a bar magnet when it is cut into two equal pieces transverse to its length becomes/remains:
- (a) Half
- (b) Double
- (c) Same
- (d) None of these
10. The material of permanent magnet has
- (a) High retentivity, low coercivity
- (b) Low retentivity,High coercivity
- (c) High retentivity, High coercivity
- (d) Low retentivity, Low coercivity
11. An electron is moving along X-axis in a magnetic field along Y-axis .The direction of magnetic force initially on it will be along
- (a) - Z-axis
- (b) + Y-axis
- (c) + Z-axis
- (d) any of the above
- (a) helix
- (b) ellipse
- (c) circle
- (d) straight line
13. How is galvanometer converted into an voltmeter?
- (a) by connecting high resistance in parallel to the galvanometer
- (b) by connecting a low resistance in parallel to the galvanometer
- (c) by connecting a high resistance in series with the galvanometer
- (d) by connecting a low resistance in series with the galvanometer
14. The angular frequency of a cyclotron is independent of
- (a) speed
- (b)mass
- (c) magnetic field
- (d) charge
15. When the plane of a current carrying coil lies perpendicular to the direction of external magnetic field then torque acting on the coil is
- (a) maximum because the magnetic field is radial
- (b) minimum but non zero
- (c) zero
- (d) dependent on the amount of current through it
- (a) 4F
- (b) 2F
- (c) F
- (d) 0
Application Based Questions
17. A proton enters a uniform magnetic field of 5 T at right angle to the field with a speed of 4 × 107m`s^{-1}`. What is the magnetic force acting on the proton?Given that charge on the proton = 1.6 × 10-19 C
- (a) 3.2 ×`10^{-13}` N
- (b) 2.3 × `10^{-13}` N
- (c) 3.0 x `10^{-11}` N
- (d) 3.2 x `10^{-11}` N
18. A solenoid of length 0.5m has radius of 1cm and is made up of 500 turns. It carries a current of 5A. What is the magnitude of magnetic field inside the solenoid?
- (a) 1.57 × `10^{-3}`T
- (b) 3.14 ×`10^{-3}`T
- (c) 4.71 × `10^{-3}`T
- (d) 6.28 × `10^{-3}`T
19. In the magnetic meridian of a certain place, the horizontal component of the earth's magnetic field is 0.26 G and the dip angle is 60o. What is the magnetic field of the earthat this location?
- (a) 0.52 G
- (b) 0.39 G
- (c) 0.26 G
- (d) 0.13 G
20. A solenoid has number of turns per meter n = 1000 turns m-1 and carries a current of2 A. The magnetic intensity or magnetising intensity H of the solenoid is given by
- (a) 2000 A/m
- (b) 2 × `10^{-3}` A/m
- (c) 500 A/m
- (d) 250 A/m
