Q.1
A car battery has emf 12Volts and internal resistance 5×10⁻²Ω. If it draws 60 amp current, the terminal voltage of the battery will be [ CBSE PMT 2000]
  • a) 15V
  • b) 3 V
  • c) 5 V
  • d) 9 V
Q.2
A moving coil galvanometer of resistance 100Ω is used as an ammeter using resistance 0.1Ω. The maximum deflection current in the galvanometer is 100µA. Find the minimum current in the circuit so that the ammeter shows maximum deflection [ IIT 2005]
  • a) 100.1 mA
  • b) 1000.1 mA
  • c)10.01 mA
  • d)1.01 mA
Q.3
A moving coil galvanometer has 150 equal divisions. Its current sensitivity is 10-divisions per milliampere and voltage sensitivity is 2 division per millivolt. In order that division reads 1 Volt, the resistance in ohm needed to be connected in series with the coil will be [ AIEEE 2005]
  • a) 105
  • b) 103
  • c)9995
  • d)99995
Q.4
In Bohr's model of hydrogen atom the electron moves around the nucleus in a circular orbit of radius 5×10⁻¹¹ metres. Its time period is 1.5×10⁻¹⁶ second. The current associated with the electron motion is [ MNR 1992]
  • a) zero
  • b) 1.6×10⁻¹⁹ A
  • c) 0.17 A
  • d) 1.07×10⁻³ A
Q.5
In a neon gas discharge tube 2.9×1018 Ne+ ions are move to the right through a cross section of tube each second, while 1.2×1018 electrons move to the left in this time. The electronic charge is 1.6×10⁻¹⁹ coulomb. Then the net electric current in the tube is [ MPPMT 1999]
  • a)1 amp to the right
  • b) 0.66 amp to the right
  • c)0.66 amp to the left
  • d)zero
Q.6
A current density of 2.5Am-2 is found to exist in conductor when an electric field of 5×10⁻⁸ Vm-1 is applied across it. The resistivity of a conductor is .. [ GSEB]
  • a) 1×10⁻⁸Ωm
  • b) 2× 10⁻⁸ Ωm
  • c) 0.5×10⁻⁸Ωm
  • d) 12.5×10⁻⁸ Ωm
Q.7
At what temperature would the resistance of copper conductor be double its resistance at 0°C? Given α for copper=3.9×10⁻³ °C-1
  • a) 256.4 °C
  • b) 512.8°C
  • c)100°C
  • d)256.4K
Q.8
In a region 1019 α-particles and 1019 protons move to the left while 1019 electrons move to the right per second./ The current is
  • a) 3.2 amp towards left
  • b) 6.4 amp towards left
  • c) 9.6 amp towards left
  • d) 6.4 amp towards right
Q.9
The belt of an electrostatic generator is 50 cm wide and travels at 30 m/sec. the belt carries charge into the sphere at a rate corresponding to 10-4 ampere. What is the surface density of charge on the belt?
  • a)6.7×10⁻⁵ C/m²
  • b) 6.7×10⁻⁶ C/m²
  • c)6.7×10⁻⁷ C/m²
  • d)6.7×10⁻⁸ C/m²
Q.10
The dimensions of a manganin ( ρ=4.4×10⁻⁷ ohm ×m) block are 1cm ×1 cm ×100 cm. The resistance between the opposite rectangular faces is
  • a)4.4 ×10⁻⁷ ohm
  • b) 4.4 ×10⁻³ ohm
  • c)4.4 ×10⁻⁵ ohm
  • d)4.4 ×10⁻¹ ohm
Q.11
In the circuit shown below, the key is pressed at time t =Which of the following statement(s) is(are) true?
ch-14_que_no-210_img_no1.png
  • a) The voltmeter displays - 5 V as soon as the key is pressed, and displays + 5 V after a long time
  • b) The voltmeter will display 0 V at time t = ln 2 seconds
  • c) The current in the ammeter becomes 1/e of the initial value after 1 second
  • d) The current in the ammeter becomes zero after a long time
Q.12
A beam of 16MeV deuterons ( charge=1.6×10⁻¹⁹ C) from a cyclotron falls on a copper block. The beam is equivalent to current of 15µA. At what rate do the deuterons strike the block?
  • a)9.4 × 1013
  • b) 9.4 × 1011
  • c)9.4 × 109
  • d)9.4 × 107
Q.13
A potentiometer wire has length 10 m and resistance 20 Ω. A 2.5V battery of negligible internal resistanceis connected across the wire with an 80Ω series resistance. The potential gradient on the wire will be:
  • a) 2.5 × 10 ×10⁻⁴ V/m
  • b) 0.62 × 10 ×10⁻⁴ V/mm
  • c)1 × 10⁻⁵ V/mm
  • d)5 × 10⁻⁵ V/mm
Q.14
In a potentiometer experiment, the balancing length is 8m when two cells E1 and E2 are joined in series. When the two cells connected in opposite the balancing length is 4 m. The ratio of the emf of two cells ( E1 / E2=is
  • a)1:2
  • b) 2:1
  • c)1:3
  • d)3:1
0 h : 0 m : 1 s