JEE Questions for Physics Current Electricity Ii Quiz 8 - MCQExams.com

An electric bulb of 100 watt is connected to a supply of electricity of 220 V . Resistance of the filament is
  • 484Ω
  • 100Ω
  • 22000Ω
  • 242Ω
If in the circuit, power dissipation is 150 W, then R is
Physics-Current Electricity II-67033.png
  • 2 Ω
  • 6 Ω
  • 5 Ω
  • 4 Ω
Find the power of the circuit
Physics-Current Electricity II-67035.png
  • 1.5 W
  • 2 W
  • 1 W
  • None of these
The heat generated through 2 ohm and 8 ohm resistances separately, when a condenser of 200µF capacity charged to 200 V is discharged one by one, will be
  • 4 J and 16 J respectively
  • 16 J and 4 J respectively
  • 4 J and 8 J respectively
  • 4 J and 4 J respectively
The heat developed in an electric wire of resistance R by a current I for at time t is

  • Physics-Current Electricity II-67038.png
  • 2)
    Physics-Current Electricity II-67039.png

  • Physics-Current Electricity II-67040.png

  • Physics-Current Electricity II-67041.png
Two bulbs, one of 50 watt and another of 25 watt are connected in series to the mains. The ratio of the currents through them is
  • 2 : 1
  • 1 : 2
  • 1 : 1
  • Without voltage, cannot be calculated
The maximum current that flows through a fuse wire before it blows out varies with its radius as
  • r3/2
  • r
  • r2/3
  • r1/2
When two resistances R1 and R2 are connected in series and parallel with 120 V line power consumed will be 25 W and 100 W respectively. Then the ratio of power consumed by R1 to that consumed by R2 will be
  • 1 : 1
  • 1 : 2
  • 2 : 1
  • 1 : 4
Match the List I with the List II from the combination shown. In the left side (List I) there are four different conditions and in the right side (List II), there are ratios of heat produced in each resistance for each condition
Physics-Current Electricity II-67046.png
  • I— B; II— A; III— C; IV— D
  • I— C; II— D; III— C; IV— D
  • I— B; II— D; III— A; IV — C
  • I — A; II— B; III — D; IV — C
The value of internal resistance of an ideal cell is
  • Zero
  • 0.5 Ω
  • 1 Ω
  • Infinity
Electric power is transmitted over long distances through conducting wires at high voltage because
  • High voltage travels faster
  • Power loss is large
  • Power loss is less
  • Generator produce electrical energy at a very high voltage
A coil develops heat of 800 cal/sec. When 20 volts is applied across its ends. The resistance of the coil is (1 cal = 4.2 joule)
  • 1.2 Ω
  • 1.4 Ω
  • 0.12 Ω
  • 0.14 Ω

Physics-Current Electricity II-67049.png

  • Physics-Current Electricity II-67050.png
  • 2)
    Physics-Current Electricity II-67051.png

  • Physics-Current Electricity II-67052.png

  • Physics-Current Electricity II-67053.png
The internal resistance of a primary cell is 4 ohm. It generates a current of 0.2 amp in an external resistance of 21 ohm. The rate at which chemical energy is consumed in providing the current is
  • 0.42 J/s
  • 0.84 J/s
  • 5 J/s
  • 1 J/s
A heating coil is labelled 100 W, 220 V. The coil is cut in half and the two pieces are joined in parallel to the same source. The energy now liberated per second is
  • 200 J
  • 400 J
  • 25 J
  • 50 J
Which of the following is not a correct statement
  • Resistivity of electrolytes decreases on increasing temperature
  • Resistance of mercury falls on decreasing its temperature
  • When joined in series a 40 W bulb glows more than a 60 W bulb
  • Resistance of 40 W bulb is less than the resistance of 60 W bulb
Three electric bulbs with same voltage ratings of 110 volts but wattage ratings of 40, 60 and 100 watts respectively are connected in series across a 220 volt supply line. If their brightness are B1, B2, B3 respectively, then
  • B1 > B2 > B3
  • B1 > B2 < B3
  • B1 = B2 = B3
  • Bulbs will burn out due to the high voltage supply
An electric iron draws 5 amp, a TV set draws 3 amp and refrigerator draws 2 amp from a 220 volt main line. The three appliances are connected in parallel. If all the three are operating at the same time, the fuse used may be of
  • 20 amp
  • 5 amp
  • 15 amp
  • 10 amp
Two bulbs of 500 watt and 200 watt are manufactured to operate on 220 volt line. The ratio of heat produced in 500 W and 200 W, in two cases, when firstly they are joined in parallel and secondly in series, will be

  • Physics-Current Electricity II-67057.png
  • 2)
    Physics-Current Electricity II-67058.png

  • Physics-Current Electricity II-67059.png

  • Physics-Current Electricity II-67060.png
A 60 watt bulb carries a current of 0.5 amp. The total charge passing through it in 1 hour is
  • 3600 coulomb
  • 3000 coulomb
  • 2400 coulomb
  • 1800 coulomb
Two conductors made of the same material are connected across a common potential difference. Conductor A has twice the diameter and twice the length of conductor B. The power delivered to the two conductors PA and PB respectively is such that PA/PB equals to
  • 0.5
  • 1.0
  • 1.5
  • 2.0
A heating coil can heat the water of a vessel from 20° C to 60° C in 30 minutes. Two such heating coils are put in series and then used to heat the same amount of water through the same temperature range. The time taken now will be (neglecting thermal capacity of the coils)
  • 60 minutes
  • 30 minutes
  • 15 minutes
  • 7.5 minutes
If 2.2 kilowatt power is transmitted through a 10 ohm line at 22000 volt, the power loss in the form of heat will be
  • 0.1 watt
  • 1 watt
  • 10 watt
  • 100 watt
Two resistors having equal resistances are joined in series and a current is passed through the combination. Neglect any variation in resistance as the temperature changes. In a given time interval
  • Equal amounts of thermal energy must be produced in the resistors
  • Unequal amounts of thermal energy may be produced
  • The temperature must rise equally in the resistors
  • The temperature must rise unequally in the resistors
Watt-hour metre measures
  • Electric energy
  • Current
  • Voltage
  • Power
Pick out the wrong statement
  • In a simple battery circuit, the point of lowest potential is the negative terminal of the battery
  • The resistance of an incandescent lamp is greater when the lamp is switched off
  • An ordinary 100 W lamp has less resistance than a 60 W lamp
  • At constant voltage, the heat developed in a uniform wire varies inversely as the length of the wire used
Two resistors of 6 Ω and 9 Ω are connected in series to a 120 volt source. The power consumed by the 6 Ω resistor is
  • 384 W
  • 576 W
  • 1500 W
  • 1200 W
If 2.2 kW power is transmitted through a 100 Ω line at 22000 V, the power loss in the form of heat will be
  • 0.1 W
  • 1 W
  • 10 W
  • 100 W
A 4µF conductor is charged to 400 volts and then its plates are joined through a resistance of 1k Ω. The heat produced in the resistance is
  • 0.16 J
  • 1.28 J
  • 0.64 J
  • 0.32 J
A 10 ohm electric heater operates on a 110 V line. Calculate the rate at which it develops heat in watts
  • 1310 W
  • 670 W
  • 810 W
  • 1210 W
Two electric bulbs A and B are rated as 60 W and 100 W. They are connected in parallel to the same source. Then
  • Both draw the same current
  • A draws more current than B
  • B draws more current than A
  • Current drawn are in the ratio of their resistances
A piece of fuse wire melts when a current of 15 ampere flows through it. With this current, if it dissipates 22.5 W, the resistance of fuse wire will be
  • Zero
  • 10 Ω
  • 1 Ω
  • 0.10 Ω
Two wires \'A\' and ‘B\' of the same material have their lengths in the ratio 1 : 2 and radii in the ratio 2 : 1. The two wires are connected in parallel across a battery. The ratio of the heat produced in \'A\' to the heat produced in ‘B\' for the same time is
  • 1 : 2
  • 2 : 1
  • 1 : 8
  • 8 : 1
A heater draws a current of 2A when connected to a 250 V source. The rate of energy dissipation is
  • 500 W
  • 1000 W
  • 250 W
  • 125 W
A bulb rated at (100 W - 200 V) is used on a 100V line. The current in the bulb is

  • Physics-Current Electricity II-67075.png
  • 2)
    Physics-Current Electricity II-67076.png

  • Physics-Current Electricity II-67077.png
  • 2 amp
A current i passes through a wire of length l, radius of cross-section r and resistivity ρ. The rate of heat generation is

  • Physics-Current Electricity II-67079.png
  • 2)
    Physics-Current Electricity II-67080.png

  • Physics-Current Electricity II-67081.png

  • Physics-Current Electricity II-67082.png
Which of the following is not equal to watt?
  • (Amp)2 × ohm
  • Amp/Volt
  • Amp × Volt
  • Joule/sec
If three bulbs 60 W, 100 W and 200 W are connected in parallel, then
  • 200 W bulb will glow more
  • 60 W bulb will glow more
  • 100 W bulb will glow more
  • All the bulbs will glow equally
If two wires having resistances R and 2 R both are joined in series and in parallel, then ratio of heat generated in this situation, applying the same voltage is
  • 2 : 1
  • 1 : 2
  • 2 : 9
  • 9 : 2
Two wires A and B of same material and mass have their lengths in the ratio 1 : 2. On connecting them to the same source, the rate of heat dissipation in B is found to be 5 W. The rate of heat dissipation in A is
  • 10 W
  • 5 W
  • 20 W
  • None of these
An electric bulb is designed to draw power P0 at voltage V0. If the voltage is V it draws a power P. Then

  • Physics-Current Electricity II-67087.png
  • 2)
    Physics-Current Electricity II-67088.png

  • Physics-Current Electricity II-67089.png

  • Physics-Current Electricity II-67090.png
An external resistance R is connected to a battery of e.m.f. V and internal resistance r. The joule heat produced in resistor R is maximum when R is equal to
  • r
  • 2)
    Physics-Current Electricity II-67092.png
  • 2r
  • Infinitely large
The amount of heat produced in a resistor when a current is passed through it can be found using
  • Faraday's Law
  • Kirchhoff's Law
  • Laplace's Law
  • Joule's Law
Two wires having resistance of 2 Ω and 4 Ω are connected to same voltage. Ratio of heat dissipated at resistance is
  • 1 : 2
  • 4 : 3
  • 2 : 1
  • 5 : 2
n identical bulbs, each designed to draw a power p from a certain voltage supply, are joined in series across that supply. The total power which they will draw is
  • p/n2
  • p/n
  • p
  • np
If two electric bulbs have 40 W and 60 W rating at 220 V, then the ratio of their resistances will be
  • 9 : 4
  • 4: 3
  • 3 : 8
  • 3 : 2
A fuse wire with radius 1 mm blows at 1.5 amp. The radius of the fuse wire of the same material to blow at 3 A will be
  • 41/3 mm
  • 31/4 mm
  • 21/2 mm
  • 31/2 mm
Two bulbs of 100 W and 200 W working at 220 volt are joined in series with 220 volt supply. Total power consumed will be approximately
  • 65 watt
  • 33 watt
  • 300 watt
  • 100 watt
How many calories of heat will be produced approximately in a 210 watt electric bulb in 5 minutes
  • 80000 cal
  • 63000 cal
  • 1050 cal
  • 15000 cal
A 100 W bulb produces an electric field of 2.9 V/m at a point 3 m away. If the bulb is replaced by 400 W bulb without disturbing other conditions, then the electric field produced at the same point is
  • 2.9 V/m
  • 3.5 V/m
  • 5 V/m
  • 5.8 V/m
  • 1.45 V/m
0:0:1


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