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

The temperature of cold junction of thermocouple is 0°C. If the neutral temperature is 270°C, then the inversion temperature is
  • 540° C
  • 520° C
  • 640° C
  • 58° C
A piece of copper and another of germanium are cooled from room temperature to 80° K. The resistance of
  • each of them increases
  • each of them decreases
  • copper increases and germanium decreases
  • copper decreases and germanium increases
An electric heater rated 220 V and 550 W is connected to AC mains. The current drawn by it is
  • 0.8 A
  • 2.5 A
  • 0.4 A
  • 1.25 A
A heater of 220 V heats a volume of water in 5 min. The same heater when connected to 110 V heats the same volume of water in (min)
  • 5
  • 20
  • 10
  • 2.5
  • 1.25
A heater coil cut into two equal parts and one part is connected with heater. Now, heat generated in heater will be
  • twice
  • half
  • one-fourth
  • four times
A 10 Ω electric heater operates on a 110 V line. The rate at which heat is developed in watts is
  • 1310 W
  • 670 W
  • 810 W
  • 1210 W
An AC generator of 220 V have internal resistance, r =10 Ω and external resistance, R =100 Ω. What is the power developed in the external circuit?
  • 227 W
  • 325 W
  • 400 W
  • 500 W

Physics-Current Electricity II-66295.png

  • Physics-Current Electricity II-66296.png
  • 2

  • Physics-Current Electricity II-66297.png
  • 18
The power dissipated across resistance R which is connected across a battery of potential V is P. If resistance is doubled, then the power becomes
  • 1/2
  • 2
  • 1/4
  • 4
A 30 V, 90 W lamp is to be operated on a 120 V DC line. For proper glow, a resistor of ....Ω should be connected in series with the lamp.
  • 40
  • 10
  • 20
  • 30
Time taken by a 836 W heater to heat one litre of water from 10°C to 40°C is
  • 30 s
  • 100 s
  • 150 s
  • 200 s
An electric bulb is rated 220 V – 100 W. The power consumed by it when operated on 110 V will be
  • 75 W
  • 40 W
  • 25 W
  • 50 W
Which factor is immaterial for the wire used in electric fuse?
  • Length
  • Radius
  • Material
  • Current
A railway compartment is lit up by thirteen lamps each taking 2.1 A at 15 V. The heat generated per second in each lamp will be
  • 4.35 cal
  • 5.73 cal
  • 7.5 cal
  • 2.5 cal
A fuse wire with radius 1 mm blows at 1.5 A. The radius of the fuse wire of the same material to blow at 3 A will be
  • 31/4 mm
  • 41/3 mm
  • 31/2 mm
  • 21/3 mm
For a thermocouple, the inversion temperature is 600°C and the neutral temperature is 320°C. Find the temperature of the cold junction?
  • 40°C
  • 20°C
  • 80°C
  • 60°C
In a thermocouple, the neutral temperature is 270°C and the temperature of inversion is 525°C. The temperature of cold junction would be
  • 30°C
  • 255°C
  • 15°C
  • 25°C
If the temperature of cold junction of thermocouple is lowered, then the neutral temperature
  • increases
  • approaches inversion temperature
  • decreases
  • remains the same
Temperature of cold junction in a thermocouple is 10°C and neutral temperature is 270°C, then the temperature of inversion is
  • 540°C
  • 530°C
  • 280°C
  • 260°C
For a given thermocouple, neutral temperature
  • is a constant
  • depends on cold junction temperature
  • depends on inversion temperature
  • double that of cold junction temperature
A lead acid battery of a car has an emf of 12 V. If the internal resistance of the battery is 0.5 Ω, the maximum current that can be drawn from the battery will be
  • 30 A
  • 20 A
  • 6 A
  • 24 A
An electric circuit contains an operating heating element and a lit lamp. Which statement best explains why the lamp remains lit when the heating element is removed from the circuit?
  • The lamp and heating element were connected in parallel
  • The lamp has less resistance than the heating element
  • The lamp has more resistance than the heating element
  • The lamp and heating element were connected in series
A 50Ω galvanometer gets full scale deflection when a current of 0.01 A pass through the coil. When it is converted to a 10 A ammeter, the shunt resistance is
  • 0.01 Ω
  • 0.05 Ω
  • 2000 Ω
  • 5000 Ω
Two electric bulbs marked 25 W–220 V and 100 W–200 V are connected in series to a 440 V supply. Which of the bulbs will fuse?
  • Both
  • 100 W
  • 25 W
  • Neither
An electric bulb marked as 50 W–200 V is connected across a 100 V supply. The present power of the bulb is
  • 37.5 W
  • 25 W
  • 12.5 W
  • 10 W
Heat is produced at a rate given by H in a resistor when it is connected across a supply of voltage V. If now the resistance of the resistor is doubled and the supply voltage is made V/3, then the rate of production of heat in the resistor will be
  • H / 18
  • H / 9
  • 6H
  • 18H
A heating coil is used to heat water in a container from 15°C to 50°C in 20 min. Two such coils are then joined in series to heat the same amount of water for the same temperature difference from the same constant voltage source. The time taken now is
  • 5 min
  • 10 min
  • 20 min
  • 40 min
When two identical batteries of internal resistance 1Ω each are connected in series across a resistor R, the rate of heat produced in R is J1. When the same batteries are conected in parallel across R, the rate is J2. If J1 = 2.25 J2, then the value of R in Ω is
  • 4
  • 6
  • 4.8
  • 5.16
A resistor R and 2μF capacitor in series is connected through a switch to 200 V direct supply. Across the capacitor is a neon bulb that lights up at 120 V. Calculate the value of R to make the bulb light up 5 s after the switch has been closed (log10 2.5 = 0.
  • 1.7 × 105 Ω
  • 2.7 × 106 Ω
  • 3.3 × 107 Ω
  • 1.3 × 104 Ω
The resistance of the filament of a lamp increases with the increase in temperature. A lamp rated 100 W and 200 V is connected across 220 V power supply. If the voltage drops by 10%, then the power of the lamp will be
  • 90 W
  • 81 W
  • between 90 and 100 W
  • between 81 and 90 W
Which of the following relation is not correct?
  • 1 ampere × 1 ohm =1 volt
  • 1 watt × 1 sec =1 joule
  • 1 newton per coulomb = lvolt per metre
  • 1 coulomb × 1 volt =1 watt
The neutral temperature, Tn = 285° C is constant for a Cu-Fe thermocouple. When the cold junction is at 0°C, the value of inversion temperature is Ti = 570° C but if the cold junction is at 10°C, the inversion temperature (Ti ) will be
  • 550°C
  • 560°C
  • 570°C
  • 580°C
A small power station supplies electricity to 5000 lamps connected in parallel. Each lamp has a resistance of 220 and is operated at 220 V. The total current supplied by the station is
  • 2500 A
  • 3500 A
  • 5000 A
  • 10000 A
If t1 and t2 are the times taken by two different coils for producing same heat with same supply, then the time taken by them to produce the same heat when connected in parallel will be
  • t1 + t2
  • 2)
    Physics-Current Electricity II-66316.png

  • Physics-Current Electricity II-66317.png
  • t1 t2
Three electric bulbs of 200 W, 200 W and 400 W are shown in figure. The resultant power of the combination is
Physics-Current Electricity II-66319.png
  • 800 W
  • 400 W
  • 200 W
  • 600 W
Two bulbs marked 200 V – 100 W and 200 V – 200 W are joined in series and connected to a power supply of 200 V. The total power consumed by the two bulbs will be near to
Physics-Current Electricity II-66321.png
  • 35 W
  • 66 W
  • 100 W
  • 300 W
Two bulbs of 250 V and 100 W are first connected in series and then in parallel with a supply of 250 V. Total power in each of the case will be respectively
  • 100 W, 50 W
  • 50 W, 100 W
  • 200 W, 150 W
  • 50 W, 200 W
Three identical resistances A,B and C are connected as shown in figure.
The heat produced will be maximum
Physics-Current Electricity II-66324.png
  • in B
  • in B and C
  • in A
  • same for A, B and C
When two resistances R1 and R2 are connected in series, they consume 12 W power. When they are connected in parallel, they consume 50 W power. What is the ratio of power of P1 and P2?
  • 1/4
  • 4
  • 3/2
  • 3
  • 1

Physics-Current Electricity II-66326.png
  • 1
  • 2
  • 0.5
  • 4
  • 0.25
In the circuit shown, if the resistance 5 Ω develops a heat of 42 Js-1, heat developed in 2 Ω must be about (in Js-1)
Physics-Current Electricity II-66328.png
  • 25
  • 20
  • 30
  • 35
  • 40
An electric water kettle rated 2.1 kW is filled with 1.5 kg of water at 20°C. How many seconds does it take to reach the boiling point of water? Assume that there are no heat losses from the kettle. Specific heat capacity of water is 4200 Jkg-1 K-1
  • 60
  • 120
  • 240
  • 480
An immersion heater with electrical resistance 7 Ω is immersed in 0.1 kg of water at 20°C for 3 min. If the flow of current is 4 A, what is the final temperature of the water in ideal conditions? (Specific heat capacity of water = 4.2 ×103 Jkg-1K-1)
  • 28°C
  • 48°C
  • 52°C
  • 68°C
Heat produced in a resistance R when a current I ampere flows through it for t seconds is given by the expression

  • Physics-Current Electricity II-66332.png
  • 2)
    Physics-Current Electricity II-66333.png

  • Physics-Current Electricity II-66334.png

  • Physics-Current Electricity II-66335.png
Two resistances R and 2R are connected in parallel in an electric circuit. The thermal energy developed in R and 2R are in the ratio
  • 1 : 2
  • 2 : 1
  • 1 : 4
  • 4 : 1
A 25 W and 100 W bulbs are joined in series and connected to the mains. Which bulb will glow brighter?
  • 25 W bulb
  • 100 W bulb
  • Both bulbs will glow brighter
  • None will glow brighter
The heat produced in 4 Ω resistance is 10 cal. The heat produced in 10 Ω resistance will be
Physics-Current Electricity II-66339.png
  • 25 cal
  • 14 cal
  • 10 cal
  • 20 cal
The voltage of clouds is 4 × 106 V with respect to ground. In a lightning strike lasting 100 ms, a charge of 4 C is delivered to the ground. The power of lightning strike is
  • 160 MW
  • 80 MW
  • 20 MW
  • 500 kW
Bulb B1 (100 W – 250 V) and bulb B2 (100 W – 200 V) are connected across 250 V. What is potential drop across B2 ?
Physics-Current Electricity II-66342.png
  • 200 V
  • 250 V
  • 98 V
  • 48 V
Two bars of radius r and 2r are kept in contact as shown. An electric current I is passed through the bars. Which one of following is correct?
Physics-Current Electricity II-66344.png
  • Heat produced in bar BC is 4 times the heat produced in bar AB
  • Electric field in both halves is equal
  • Current density across AB is double that of across BC
  • Potential difference across AB is 4 times that of across BC
0:0:1


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