Term I Exam Revision Test Paper 1 Class XII Subject Physics Time 1.5 hr Multiple Choice Questions MM 35
1. The scientist whose name is not associated with the electromagnetic waves is
- a) Hertz
- b) Jagdish Chandra Bose
- c) Marconi
- d) Huygens
- d) Huygens
2. Dielectric constant of a metal is
- a) 1
- b) 0
- c) ∞
- d) Indefinite
- c) ∞
3. Which is one of the best materials for making connecting wires?
- a) Manganin
- b) Constantan
- c) Copper
- d) Nichrome
- c) Copper
4. If an electron is brought toward an another electron, the electric potential energy of the system
- a) Increases
- b) decreases
- c) become zero
- d) remains the same
- a) Increases
5. Kirchhoff’s first law is based on
- a) the law of conservation of momentum
- b) the law of conservation of electric charge
- c) principle of quantisation of charge
- d) the law of conservation of kinetic energy
- b) the law of conservation of electric charge
6. Principle of Wheatstone’s bridge is used in
- a) Galvanometer
- b) Meter Bridge
- c) ammeter
- d) voltmeter
- b) Meter Bridge
7 . Magnetic susceptibility of a paramagnetic substance is
- a) small and positive
- b) small and negative
- c) large and positive
- d) large and negative
- a) small and positive
8. Value of Bohr magneton is
- a) 𝑒ℎ/2𝜋𝑚𝑒
- b) 𝑒ℎ/2𝑚𝑒
- c) 𝑒ℎ/4𝜋𝑚𝑒
- d) None of these
- c) 𝑒ℎ/4𝜋𝑚𝑒
9. Weber m⁻² is equal to
- a) tesla
- b) henry
- c) watt
- d) dyne
- a) tesla
10. An induction furnace works on the principle of
- a) eddy currents
- b) Faraday's laws
- c) self-induction
- d) mutual induction
- a) eddy currents
11. The direction of induced e.m.f is given by
- a) Coulomb's laws
- b) lenz's law
- c) Lorentz’s law
- d) Ampere’s law
- b) lenz's law
12. What is a shunt?
- a) low resistance
- b) high resistance
- c) Both
- d) none of these
- a) low resistance
13. Which of the following have shortest frequency?
- a) microwaves
- b) visible light
- c) X-rays
- d) gamma rays
- a) microwaves
14. Torque acting on a dipole placed in electric field is maximum when angle between 𝑃⃗⃗ and 𝐸⃗⃗⃗ is
- a) 0⁰
- b) 90⁰
- c) 45⁰
- d) 180⁰
- b) 90⁰
15. When area of cross-section of copper wire is doubled, keeping its length same, then its resistance is
- a) Doubled
- b) halved
- c) no change
- d) one of these
- a) Doubled
16. A charge Q is enclosed by a gaussian spherical surface of radius R. If the radius is doubled, then the outward electric flux will
- a) increase four times
- b) be reduced to half
- c) remain the same
- d) be doubled
- c) remain the same
17. An electric dipole placed in a non uniform electric field experiences
- a) both , a torque and a net force
- b) only a force but no torque
- c) only a torque but no net force
- d) no torque and no net force
- a) both , a torque and a net force
18. The physical quantity which has unit NC⁻ ¹ is
- a) Electric potential
- b) Electric field
- c) Force
- d) Work
- b) Electric field
19. With increase in temperature, the resistivity of a conductor
- a) Increases
- b) decreases
- c) may increase or decrease
- d) does not change
- a) Increases
20. The specific resistance of a material depends on:
- a) length of the conductor
- b) area of cross section of the conductor
- c) both length and area of the conductor
- d) nature and temperature of the material
- d) nature and temperature of the material
21. Resistance of a semiconductor decreases with the rise of temperature, because
- a) relaxation time and electron density decrease
- b) relaxation time and electron density increases
- c) electron density decreases and relaxation time increases, the second factor dominates the first.
- d) electron density increases and relaxation time decreases, the first factor dominates the second
- d) electron density increases and relaxation time decreases, the first factor dominates the second
22. The path of an electron in a uniform magnetic field may be
- a) circular but not helical
- b) helical but not circular
- c) neither helical nor circular
- d) either helical or circular
- d) either helical or circular
23. A permanent magnet has the properties of retentivity and coercivity, which in magnitude are respectively
- a) high - high
- b) Low - low
- c) Low – high
- d) High - low
- c) Low – high
24. Two streams of electrons moving parallel to each other in opposite direction will
- a) attract each other
- b) repel each other
- c) cancel the magnetic field of each other
- d) cancel the electric field of each other
- b) repel each other
25. At which place on earth, the earth’s magnetic field becomes horizontal
- a) magnetic pole
- b) geographical pole
- c) magnetic meridian
- d) magnetic equator
- d) magnetic equator
26. Phase difference between the voltage drop across L and R in a series LCR circuit connected to an a.c. source is
- a) 0⁰
- b) 180⁰
- c) 90⁰
- d) 360⁰
- c) 90⁰
27. Power factor is 1 for
- a) pure inductor
- b) pure capacitor
- c) pure resistor
- d)either an inductor or a capacitor
- c) pure resistor
28. The core used in transformers and other electromagnetic devices is laminated, so as
- a) to reduce the magnetism in the core
- b) to reduce eddy current losses in the core
- c) to increase the magnetic field
- d) to increase the magnetic flux
- b) to reduce eddy current losses in the core
29. A galvanometer having a resistance of 100 Ω gives full scale deflection with 0.01 A current. How much resistance should be connected to convert it into an ammeter of range 10 A ?
- a) 0.1Ω in parallel
- b) 0.1Ω in series
- c) 10 Ω in parallel
- d) 10 Ω in series
- a) 0.1Ω in parallel
30. The rms value of an a.c.is 5 A. Its maximum value will be
- a) 10 A
- b) 5 √2 A
- c) 5 / √2 A
- d) 5 √3 A
- b) 5 √2 A
31. How many electrons are there in a charge of -1 micro coulomb?
- a) 6.25 × 10¹²
- b) 1.6 × 10⁻¹³
- c) 6.25 × 10¹⁸
- d) 1.6 × 10¹³
- a) 6.25 × 10¹²
32. There are two charges of + 4 micro coulomb and + 2 micro coulomb separated by a distance of 0.1 m in air. The ratio of the forces acting on them will be
- a) 4:1
- b) 2:1
- c) 1:2
- d) 1:1
- a) 4:1
33. A source is transmitting electromagnetic waves of frequency 9 ×10⁶ Hz. Then the wavelength of the electromagnetic waves transmitted from the source will be
- a) 36.6 m
- b) 40. 5
- c) 33.3 m
- d) 50.9 m
- c) 33.3 m
34.A wire of resistance 1 ohm is elongated by 10%. The resistance of the elongated wire is
- a) 11 Ω
- b) 11.1 Ω
- c) 1.21 Ω
- d) 13.1 Ω
- c) 1.21 Ω
35. A proton enters a uniform magnetic field of 5 T at right angle to the field with a speed of 4× 10⁷ ms⁻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
- d) 3.2 x 10⁻¹¹ N
