JEE Questions for Physics Current Electricity I Quiz 1 - MCQExams.com

Which of the following has a negative temperature coefficient?
  • C
  • Fe
  • Mn
  • Ag
The reciprocal of resistance is
  • Conductance
  • Resistivity
  • Voltage
  • None of these
The temperature coefficient of resistance of a wire is 0.00125 per °C. At 300 K, its resistance is 1 ohm. This resistance of the wire will be 2 ohm at.
  • 1154 K
  • 1100 K
  • 1400 K
  • 1127 K
If a wire is stretched to make it 0.1% longer, its resistance will
  • increase by 0.2%
  • decrease by 0.2%
  • decrease by 0.05%
  • increase by 0.05%
The resistance of a 10 m long wire is 10Ω . Its length is increased by 25% by stretching the wire uniformly. Then, the resistance of the wire will be
  • 12.5 Ω
  • 14.5 Ω
  • 15.6 Ω
  • 16.6 Ω
  • 18.6 Ω
The masses of the three wires of copper are in the ratio 5 : 3: 1 and their lengths are in the ratio 1 : 3 : 5. The ratio of their electrical resistance is
  • 5 : 3 : 1
  • √125 : 15 : 1
  • 1: 15: 125
  • 1 : 3 : 5
The amount of charge Q passed in time t through a cross-section of a wire is Q = 5t2 + 3t + 1. The value of current at time t = 5 s is
  • 9 A
  • 49 A
  • 53 A
  • None of these
Resistance of a wire at 20°C is 20 Ω and at 500°C is 60Ω . At what temperature its resistance is 25 Ω ?
  • 160°C
  • 250°C
  • 100°C
  • 80°C
The resistance of a metal increases with increasing temperature because
  • the collisions of the conducting electrons with the electrons increase
  • the collisions of the conducting electrons with the lattice consisting of the ions of the metal increases
  • the number of conduction electrons decrease
  • the number of conduction electrons increase
In the circuit shown in fig the heat produced in the 5 ohm resistor due to the current flowing through it is 10 calories per second.
Physics-Current Electricity I-64408.png
  • 1 calorie / sec
  • 2 calories /sec
  • 3 calories /sec
  • 4 calories /sec
Identify the incorrect statement regarding a superconducting wire
  • transport current flows through its surface
  • transport current flows through the entire area of cross-section of the wire
  • it exhibits zero electrical resistivity and expels applied magnetic field
  • it is used to produce large magnetic field
With the rise of temperature the resistivity of a semiconductor
  • remains unchanged
  • increases
  • decreases
  • first increases and then decreases
A metal wire is subjected to a constant potential difference. When the temperature of the metal wire increases, the drift velocity of the electron in it
  • increases, thermal velocity of the electron decreases
  • decreases, thermal velocity of the electron decreases
  • increases, thermal velocity of the electron increases
  • decreases, thermal velocity of the electron increases
The resistance of a straight conductor does not depend on its
  • length
  • temperature
  • material
  • shape of cross - section
An electric current passes through a circuit containing two wires of the same material connected in parallel. If the lengths of the wires are in the ratio of 4/3 and radius of the wires are in the ratio of 2/3, then the ratio of the currents passing through the wires will be
  • 3
  • 1/3
  • 8/9
  • None of these
Metals have
  • zero resistivity
  • high resistivity
  • low resistivity
  • infinite resistivity
The electron dirft speed is small and the charge of the electron is also small but still, we obtain large current in a conductor. This is due to
  • the conducting property of the conductor
  • the resistance of the conductor is small
  • the electron number density of the conductor is small
  • the electron number density of the conductor is enormous
The resistance of a wire is 5 Ω at 50°C and 6Ω at 100°C. The resistance of the wire at 0°C will be
  • 2Ω
  • 1Ω
  • 4Ω
  • 3Ω
The length of a given cylindrical wire is increased by 100%. Due to the consequent decrease in diameter the change in the resistance of the wire will be
  • 200%
  • 100%
  • 50%
  • 300%
In which of the following substances does resistance decrease with increase in temperature?
  • Copper
  • Carbon
  • Constantan
  • Silver
An aluminium (resistivity p = 2.2 × 10–8 Ω -m) wire of a diameter 1.4 mm is used to make a 4 Ω resistor. The length of the wire is
  • 220 m
  • 1000 m
  • 280 m
  • 1 m
The thermistors are usually made of
  • metals with low temperature coefficient of resistivity
  • metals with high temperature coefficient of resistivity
  • metal oxides with high temperature coefficient of resistivity
  • semiconducting materials having low temperature coefficient of resistivity
A potential difference is applied across the ends of a metallic wire. If the potential difference is doubled, the drift velocity will
  • be doubled
  • be halved
  • be quadrupled
  • remain unchanged
Two resistances R and 2R are connected in parallel in an electric circuit. The thermal energy developed in R and 2R is in the ratio
  • 1 : 2
  • 1 : 4
  • 4 : 1
  • 2 : 1
A wire of resistance 18Ω is divided into three equal parts. These parts are connected in side of triangle, the equivalent resistance of any two corners of triangle will be
  • 18Ω
  • 9Ω
  • 6Ω
  • 4Ω
A metallic wire of resistance 12 Ω is bent to form a square. The resistance between two diagonal points would be
  • 12Ω
  • 24Ω
  • 6Ω
  • 3Ω
Resistance of rod is 1Ω It is bent in form of square. What is resistance across adjoint comers ?
  • 1Ω
  • 3Ω

  • Physics-Current Electricity I-64419.png

  • Physics-Current Electricity I-64420.png
How many minimum number of 2Ω resistance can be connected to have an effective resistance of 1.5Ω?
  • 3
  • 2
  • 4
  • 6
The resistance of the series combination of two resistances is S. When they are joined in parallel, the total resistance is P. If S = nP, then the minimum possible value of n is
  • 4
  • 3
  • 2
  • 1
Kirchhoff s second law for the analysis of circuit is based on
  • conservation of charge
  • conservation of energy
  • conservation of both charge and energy
  • conservation of momentum of electron
The resistance of ideal voltmeter is
  • zero
  • greater than zero but finite value
  • infinite
  • 5000 Ω
A current 4.0 A exist in a wire of cross-sectional area 2.0 mm2.If each cubic metre of the wire contains 12.0 × 1028 free electrons then the drift speed is
  • 2 × 10-8 m/s
  • 0.5 × 10-3 m/s
  • 1.04 × 10-4 m/s
  • None of these
A carbon film resistor has colour code green, black, violet, and gold. The value of the resistor is
  • 50 MΩ
  • 500 MΩ
  • 500 ± 5% MΩ
  • 500 ± 10% MΩ
Two conductors are made of the same material and have the same length. Conductor A is a solid wire of diameter 1.0 mm and conductor B is a hollow tube of outside diameter 2.0 mm and inside diameter 1.0 mm. Find the resistance ratio RA /RB measured between their ends
  • 3
  • 2
  • 1
  • 0.5
A constant voltage is applied between the two ends of a uniform metallic wire. Some heat is developed in it. The heat developed is doubled if
  • both the length and the radius of the wire are halved.
  • both the length and the radius of the wire are doubled.
  • the radius of the wire is doubled.
  • the length of the wire is doubled.
A silver wire has a resistance of 1.6Ω at 25.5° C and a resistance of 2.5Ω at 100° C , then temperature coefficient of resistivity of silver is
  • 5.55 × 10-3 °C-1
  • 7.55 × 10-3 °C-1
  • 11.75 × 10-3 °C-1
  • 15.5 × 10-3 °C-1

Physics-Current Electricity I-64428.png
  • Intensity of light from a point source.
  • Electrostatic potential due to a point charge.
  • Electrostatic potential at a distance r from the centre of a charged metallic sphere. Given r < radius of the sphere.
  • None of these
Find the true statement.
  • Ohm's law is applicable to all conductors of electricity
  • In an electrolyte solution, the electric current is mainly due to the movement of electrons
  • The resistance of an incandescent lamp is lesser when the lamp is switched on
  • Specific resistance of a wire depends upon its dimension
  • The resistance of carbon decreases with the increase of temperature
Consider a thin square sheet of side L and thickness t, made of a material of resistivity ρ. The resistance between two opposite faces, shown by the shaded areas in the figure is,
Physics-Current Electricity I-64429.png
  • directly proportional to L
  • directly proportional to t
  • independent of L
  • independent of t
A battery of emf E has an internal resistance r. A variable resistance R is connected to the terminals of the battery. A current i is drawn from the battery. V is the terminal potential difference. If R alone is gradually reduced to zero, which of the following best describes i and V?
  • i approaches zero, V approaches E
  • 2)
    Physics-Current Electricity I-64431.png

  • Physics-Current Electricity I-64432.png
  • i approaches infinity, V approaches E
The density of copper is 9 × 103 kg/m3 and its atomic mass is 63.5 u. Each copper atom provides one free electron. Estimate the number of free electrons per cubic metre in copper.
  • 1019
  • 1023
  • 1025
  • 1028
For the circuit shown in the figure.
Physics-Current Electricity I-64435.png
  • the current I through the battery is 7.5 mA
  • the potential difference across RL is 18 V
  • ratio of powers dissipated in R1 and R2 is 3
  • if R1 and R2 are interchanged, magnitude of the power dissipated in RL will increase by a factor of 9
Equal amounts of a metal are converted into cylindrical wires of different lengths Land cross-sectional area A. The wire with the maximum resistance is the one, which has
  • length = Land area = A
  • 2)
    Physics-Current Electricity I-64437.png

  • Physics-Current Electricity I-64438.png
  • All have the same resistance, as the amount of the metal is the same
If the resistivity of an alloy is ρ' and that of constituent metal is p then,
  • ρ' > ρ
  • ρ' < ρ
  • ρ' = ρ
  • there is no simple relation between ρ and ρ'
160 W 60 V lamp is connected at 60 V DC supply. The number of electrons passing through the lamp in 1 min is
(The charge of electron, e = 1.6 × 10-19 C)
  • 1019
  • 1021
  • 1.6 × 1019
  • 1.4 × 1020
The resistance of a wire at 300 K is found to be 0.3 Ω. . If the temperature coefficient of resistance of wire is 1.5 × 10-3 K-1, the temperature at which the resistance becomes 0.6 Ω is
  • 720 K
  • 345 K
  • 993 K
  • 690 K
The drift velocity of the electrons in a copper wire of length 2 m under the application of a potential difference of 220 V is 0.5 ms -1. Their mobility (in m2 V-1 s -1 )
  • 2.5 × 10-3
  • 2.5 × 10-2
  • 5 × 102
  • 5 × 10-3
  • 5 × 10-2
An aluminium (Al) rod with area of cross-section 4 × 10-6 m2 has a current of 5 A flowing through it. Find the drift velocity of electron in the rod. Density of Al = 2.7 × 103 kgm-3 and atomic weight = 27 u. Assume that each Al atom provides one electron.
  • 8.6 × 10-4
  • 1.3 × 10-4
  • 2.8 × 10-2
  • 3.8 × 10-3
Two wires have lengths, diameters and specific resistances all in the ratio of 1: 2. The resistance of the first wire is 10 Ω. Resistance of the second wire in ohm will be
  • 5
  • 10
  • 20
  • infinite
If a rod has resistance 4Ω and if rod is turned as half circle, then the resistance along diameter is
  • 1.56Ω
  • 2.44Ω
  • 4Ω
  • 2Ω
0:0:1


Answered Not Answered Not Visited Correct : 0 Incorrect : 0

Practice Physics Quiz Questions and Answers