Term I Exam Revision Test Paper 2 Class XII Subject Physics
Time 1.5 hr Multiple Choice Questions Dated: 02.12.2021 MM 35
1. Question paper has 35 multiple choice questions.
2. Each question is compulsory.
MULTIPLE CHOICE QUESTIONS:
1. Equipotential surfaces
- (a) are closer in regions of large electric fields compared to regions of lower electric fields
- (b) will be less crowded near sharp edges of a conductor
- (c) will always be equally spaced
- (d) both (a) and (b) are correct
2. When air is replaced by a dielectric medium of constant K, the maximum force of attraction between two charges separated by a distance r
- (a) changes to K times (F' = KF)
- (b) remains unchanged (F' = F)
- (c) changes to K-1 times (F' = F/K)
- (d) changes to K-2 times (F' = F/K2)
3. When we rub a glass rod with silk, then the glass rod acquires positive charge and silk cloth acquires negative charge. In this process
- (a) Mass of the glass rod increases
- (b) Mass of silk decreases
- (c) Mass of glass rod decreases
- (d) Mass of glass rod & silk increases
4. Consider a uniform electric field in the z-direction. The potential is a constant
- (a) on the x-z plane for a given y
- (b) on the y-z plane for a given x
- (c) on the x-y plane for a given z
- (d) all of these
5. The best instrument for accurate measurement of EMF of a cell is
- (a) wheatstone bridge
- (b) ammeter
- (c) a potentiometer
- (d) voltmeter
6. Of the following is not the mathematical statement of Ohm's Law
- (a) V =IR
- (b) J = ╧ГE
- (c) E= J╧Б
- (d) R = ╧Б l/A
7. Which of the following is not a unit of magnetic induction (B)?
- (a) gauss
- (b) tesla
- (c) oersted
- (d) weber/meter²
8. 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) Negative Z-axis ( using Fleming's Left Hand rule)
- (b) Y-axis
- (c) Positive Z-axis
- (d) any of the above
9. Which of the following independent quantities is not used to specify earth’s magnetic field?
- (a) Magnetic declination (╬╕)
- (b) Magnetic dip (ЁЭЫ┐)
- (c) Horizontal component of earth’s field (BЁЯЗн)
- (d) Vertical component of earth’s field (Bс╡е)
10. Transformer is based on the principle of:
- (a) Self induction
- (b) Mutual induction
- (c) Eddy currents
- (d) None of these
11. In an AC circuit having pure inductor:
- (a) Current leads voltage by 90°
- (b) Current lags behind voltage by 90°
- (c) Both are in phase
- (d) None of the above
12. Infrared spectrum lies between:
- (a) Radio waves and microwaves
- (b) Micro and visible region
- (c) Visible and UV
- (d) UV and X rays
13. A charged comb attracts pieces of paper. Why does this happen?
- (a) paper also gets charged
- (b) Paper has no change
- (c) Paper is polarized
- (d) none of these
14. A capacitor has some dielectric between its plates, and the capacitor is connected to a dc source. The battery is now disconnected and then the dielectric is removed, then
- (a) capacitance will increase
- (b) energy stored will decrease
- (c) electric field will increase
- (d) voltage will decrease
15. A hollow metal sphere of radius 5 cm is charged so that the potential on its surfaceis 10 V. The potential at the centre of the sphere is
- (a) 0 V
- (b) 10 V
- (c) Same as at point 5 cm away from the surface
- (d) Same as at point 25 cm away from the surface
16. The electric field is a conservative field. It means that
- (a)Electric lines always make closed loops
- (b) Work done by external agency in moving a charge from one point to another in this field is always zero
- (c) Work done by electric field in moving a charge from one point to another in this field depends on the path between these two points
- (d) Work done by external force or electric force in moving a charge over any closed path in this field is always zero
17. From the following graph of a device? What you have concluded?
- (a) An Ohmic device. The resistance is constant for all currents and voltage values.
- (b) An Ohmic device. The resistance is variable for all currents and voltage values shown by
- changing the gradient of the graph.
- (c) Non-Ohmic device. The resistance is constant for all currents and voltage valuesshown by same gradient.
- (d) Non-Ohmic device. The resistance is variable for all currents and voltage values shown by changing the gradient of the graph.
18. Which of the following expressions is in accordance with Kirchoff first law?
- (a) I1 + I2 + I3 = I4 + I5
- (b) I1 - I2 + I3 = I4 + I5
- (c) I1 + I2 - I3 = I4 - I5
- (d) I1 - I2 + I3 = I4 - I5
19. A potentiometer is used to measure the emf of a cell. At null point, no current flow through
- (a) the main circuit
- (b) the cell circuit
- (c) both main and cell circuit
- (d) the potentiometer wire
20. Suspension wire used tin moving coil galvanometer is made up of Phosphor Bronze because:
- (a) It has small restoring torque per unit twist
- (b) It can bear high temperature
- (c) It has small resistance
- (d) It cannot break easily
21. The earth’s core has iron but it is not regarded as source of earth’s magnetism because:
- (a) Iron does not show magnetic properties
- (b) Temperature of earth’s core is very high and at this temperature iron does not remain ferromagnetic
- (c) Iron is a superconducting material
- (d) None of these
22.A proton and electron with equal momenta enter normal to magnetic field, then:
- (a) Both remain unaffected
- (b) Path of electron will be more curved than proton
- (c) Path of proton will be more curved than electron
- (d) Path of both particles will be equally curved.
23. A charged particle enters a non uniform magnetic field and comes out of it following a complicated trajectory. Then
- (a) Kinetic energy of particle increases
- (b) Kinetic energy of particle remains same
- (c) Kinetic energy of particle decreases
- (d) Kinetic energy first increases and then decreases
24. Which of the following statements is true for the force and torque acting on a current carrying loop placed in a uniform magnetic field?
- (a)Force acting on loop is always zero and torque may not be zero
- (b) Torque acting on loop is always zero and force may not be zero
- (c) Both force and torque acting on the current carrying loop are always zero
- (d) Force as well as torque acting on the current carrying loop can never be zero
25. AC is considered more dangerous than DC because:
- (a) Peak value to AC is equal to its indicated value
- (b) Peak value of AC is more than its indicated value
- (c) Peak value of DC is less than its indicated value
- (d) None of these
- (a) L blocks both direct current and high frequency alternating current
- (b) C blocks both direct current and high frequency alternating current
- (c) L blocks direct current and C blocks high frequency alternating current
- (d) C blocks direct current and L blocks high frequency alternating current
27.A flexible wire of irregular shape, abed as shown in the figure, turns into a circular shape when placed in a region field which is directed normal to the plane of the loop away from the reader. Predict the direction of the induced current in the wire.
- (a) a→b→c→d or clockwise
- (b) a→d→c→b or anticlockwise
- (c) Direction of current depends on the opening the wire
- (d) No current is induced at all
28. Which of the following statement is false for the properties of electromagnetic waves?
- (a) Both electric and magnetic field vectors attain the maxima and minima at the same place and same time.
- (b) The energy in electromagnetic waves is divided equally between electric and magnetic field vectors.
- (c) Both electric and magnetic field vectors are parallel to each other and perpendicular to the direction of propagation of wave.
- (d) These waves do not require any material medium for propagation.
29. What is the wave length of a television station, which transmits vision on 500 MHz
- (a) 1m
- (b) 500m
- (c) 0.6 m
- (d) 36.7 m
30. 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
31. A series circuit with L=0.12 H, C= 0.48 ╬╝F and R=25 ohm, is connected to a 220V variable frequency power to the conductor. Find the value of angular frequency at which current amplitude is maximum.
- (a) 3.255 × 103rad s⁻¹
- (b) 5.291 × 103rad s⁻¹
- (c) 6.343 × 103rad s⁻¹
- (d) 4.167 × 103 rad s⁻¹
32. A galvanometer coil has a resistance of 12 ╬й and the meter shows full scale deflection for a current of 3 mA. We can convert it into a voltmeter of range 0 – 18V by
- (a) Connecting a resistance of 5988 ╬й in series with the galvanometer coil
- (b) Connecting a resistance of 5988 ╬й in parallel with the galvanometer coil
- (c) Connecting a resistance of 0.024 ╬й in series with the galvanometer coil
- (d) Connecting a resistance of 0.024 ╬й in parallel with the galvanometer coil
33. A cell of e.m.f 1.0 V gives a balance point at 40 cm length of a potentiometer wire. For another cell, the balance point is shift to 50 cm. Find the e.m.f of the cell.
- (a) 3.25 V
- (b) 1.25 V
- (c) 2.25 V
- (d) 1.5 V
- (a) 4
- (b) 9
- (c) 12
- (d) 2
35. Two point charges of +16╬╝ C and -9╬╝ C are placed 8 cm apart in air. Determine the position of a point at which the resultant electric field is zero.
- (a) At a distance of 24 cm from -9╬╝C charge on its right side
- (b) At a distance of 32 cm from +16╬╝C charge on its left side
- (c) At a distance of 24 cm from +16╬╝C charge on its left side
- (d) At the middle point of line joining two charges
