Electricity

Q1: Which of the given is the SI Unit of Electric Current?

• Ohm
• Ampere
• Volt
• Faraday

Q2: What is the amount of current flowing through an electric press, if the amount of charge passing through a conductor in 10 minutes is 300 C?

• 30 A
• 0.3 A
• 0.5 A
• 5 A

Q3: When electric current is passed, electrons move from:

• high potential to low potential.
• low potential to high potential.
• in the direction of the current.
• against the direction of the current.

Q4: A wire of length /, made of material resistivity ρ is cut into two equal parts. The resistivity of the two parts are equal to,

• ρ
• P/2
• 2 ρ
• 4 ρ

Q5: The hindrance presented by material of conductor to the smooth passing of electric current is known as:

• Resistance
• Conductance
• Inductance
• None of these

Q6: An electrical appliance has a resistance of 25 Ω. When this electrical appliance is connected to a 230 V supply line, the current passing through it will be:

• 0.92 A
• 2.9 A
• 9.2 A
• 92 A

Q7: The heating element of an electric iron is made up of:

• copper
• nichrome
• aluminium
• iron

Q8: A fuse wire is inserted in which wire?

• Live wire
• In the neutral wire
• In the earth wire
• May be connected in any line

Q9: When a 4 Ω resistor is connected across the terminals of a 2 V battery, the number of coulombs passing through the resistor per second is:

• 0.5
• 1
• 2
• 4

Q10: The electrical resistance of insulators is

• high
• low
• zero
• infinitely high

Q11: A battery of 10 volt carries 20,000 C of charge through a resistance of 20 Ω. The work done in 10 seconds is

• 2 × 10³ joule
• 2 × 10⁵ joule
• 2 × 10⁴ joule
• 2 × 10² joule

Q12: The rate of flow of an electric charge is known as :

• Electric potential
• Electric conductance
• Electric current
• None of these

Q13: Keeping the potential difference constant, the resistance of the circuit is halved. The current will become:

• One-fourth
• Four times
• Half
• Double

Q14: Electrical resistivity of any given metallic wire depends upon

• its thickness
• its shape
• nature of the material
• its length

Q15: A boy records that 4000 joule of work is required to transfer 10 coulomb of charge between two points of a resistor of 50 Ω. The current passing through it is

• 2 A
• 4 A
• 8 A
• 16 A

Q16: The instrument used for measuring electric current is :

• Ammeter
• Galvanometer
• Voltmeter
• Potentiometer

Q17: If in the given arrangement, the three resistors are to be replaced by a single resistor. What will be the value of this resistor?

• 4Ω
• 6Ω
• 9Ω
• 18Ω

Q18: Electric power is inversely proportional to

• resistance
• voltage
• current
• temperature

Q19: The amount of work done in joules, when one unit electric charge moves from one point to another point in an electric circuit is called :

• Electric current
• Electric resistance
• Electric conductance
• Potential difference

Q20: The potential difference across the 3 Ω resistor in the following diagram is:

• 1/9 V
• 1/2 V
• 2V
• 1V

Q21: What is the commercial unit of electrical energy?

• Joules
• Kilojoules
• Kilowatt-hour
• Watt-hour

Q22: To get 2 Ω resistance using only 6 Ω resistors, the number of them required is

• 2
• 3
• 4
• 6

Q23: The unit of potential difference is :

• Volt
• Ohm
• Ampere
• Faraday

Q24: V1, V2 and V3 are the potential differences across the 1Ω, 2Ω and 3Ω resistors in the following diagram, and the current is 5A. Which of the following shows the correct values of V1, V2 and V3 measured in volts?

• V1 =1, V2 = 2 and V3 = 3
• V1 =5, V2 = 10 and V3 = 15
• V1 =5, V2 = 2.5 and V3 = 1.6
• V1 =4, V2 = 3 and V3 = 2

Q25: Three resistors of 1 Ω, 2 ft and 3 Ω are connected in parallel. The combined resistance of the three resistors should be

• greater than 3 Ω
• less than 1 Ω
• equal to 2 Ω
• between 1 Ω and 3 Ω

Q26: Two devices are connected between two points say A and B in parallel. The physical quantity that will remain the same between the two points is

• current
• voltage
• resistance
• None of these

Q27: The relation between potential difference (V) and current (I) is :

• V α I2
• V α 1/I
• V2 α I
• V α I

Q28: A wire of resistance R1 is cut into five equal pieces. These five pieces of wire are then connected in parallel. If the resultant resistance of this combination be R2, then the ratio R1/ R2 is:

• 1/25
• 1/5
• 5
• 25

Q29: An electric bulb is connected to a 220V generator. The current is 0.50 A. What is the power of the bulb?

• 440 W
• 110 W
• 55 W
• 0.0023 W

Q30: Calculate the current flows through the 10 Ω resistor in the following circuit.

• 1.2 A
• 0.6 A
• 0.2 A
• 2.0 A

Q31: The relation between potential difference (V) and current (I) was discovered by :

• Newton
• Ampere
• Ohm
• Volta

Q32: Two appliances of rating 200 watt-250 volts and 100 watt-250 volts are joined in series to a 250 volts supply. Total power consumed in the circuit is

• 46 watt
• 67 watt
• 10 watt
• 30 watt

Q33: The resistivity of insulators is of the order of

• 10-⁸ Ω-m
• 10¹ Ω-m
• 10-⁶ Ω-m
• 10⁶ Ω-m

Q34: Two resistors are connected in series gives an equivalent resistance of 10 Ω. When connected in parallel, gives 2.4 Ω. Then the individual resistance are

• each of 5 Ω
• 6 Ω and 4 Ω
• 7 Ω and 4 Ω
• 8 Ω and 2 Ω

Q35: The obstruction offered by material of conductor to the passage of electric current is known as :

• Resistance
• Conductance
• Inductance
• None of these

Q36: When a current ‘I’ flows through a resistance ‘R’ for time ‘t’ the electrical energy spent is given by

• IRt
• I²Rt
• IR²t
• I²R/t

Q37: Two electric bulbs have resistances in the ratio 1:2. If they are joined in series, the energy consumed in them is in the ratio.

• 2:1
• 1:2
• 4:1
• 1:1

Q38: You are given four ammeters A, B, C and D having least counts mentioned below: I. Ammeter A with least count 0.25 A II. Ammeter B with least count 0.5 A III. Ammeter C with least count 0.05 A IV. Ammeter D with least count 0.1 A Which of the ammeters would you prefer for doing an experiment to determine the equivalent resistance of two resistances most accurately, when connected in parallel?

• Ammeter A
• Ammeter B
• Ammeter C
• Ammeter D

Q39: At a given time, a house is supplied with 100 A at 220 V. How many 75 W, 220 V light bulbs could be switched on in the house at the same time (if they are all connected in parallel)?

• 93
• 193
• 293
• 393

Q40: If the current flowing through a fixed resistor is halved, the heat produced in it will become:

• One-fourth
• One-half
• Double
• Four times

Q41: Coulomb is the SI unit of:

• charge
• current
• potential difference
• resistance

Q42: 1 mV is equal to:

• 10 volt
• 1000 volt
• 10-³ volt
• 10-⁶ volt

Q43: Electric potential is a:

• scalar quantity
• vector quantity
• neither scalar nor vector
• sometimes scalar and sometimes vector

Q44: 100 J of heat is produced each second in a 4Ω resistor. The potential difference across the resistor will be:

• 30 V
• 10 V
• 20 V
• 25 V

Q45: Which of the following gases are filled in electric bulbs?

• Helium and Neon
• Neon and Argon
• Argon and Hydrogen
• Argon and Nitrogen

Q46: 1 kWh = ……….. J

• 3.6 × 10-⁶ J
• 13.6 × 10⁶ J
• 3.6 × 10⁶ J
• 13.6 × 10-⁶ J

Q47: If R1 and R2 be the resistance of the filament of 40 W and 60 W respectively operating 220 V, then

• R1 < R2
• R2 < R1
• R1 = R2
• R1 ≥ R2

Q48: The resistance of hot filament of the bulb is about 10 times the cold resistance. What will be the resistance of 100 W-220 V lamp, when not in use?

• 48 Ω
• 400 Ω
• 484 Ω
• 48.4 Ω

Q49: A coil in the heater consume power P on passing current. If it is cut into halves and joined in parallel, it will consume power

• P
• P/2
• 2P
• 4P

Q50: A fuse wire repeatedly gets burnt when used with a good heater. It is advised to use a fuse wire of

• more length
• less radius
• less length
• more radius

Q51: A cooler of 1500 W, 200 volt and a fan of 500 W, 200 volt are to be used from a household supply. The rating of fuse to be used is

• 2.5 A
• 5.0 A
• 7.5 A
• 10 A

Q52: The effective resistance between A and B is

• 4Ω
• 6Ω
• May be 10 Ω
• Must be 10 Ω

Q53: A current of 1 A is drawn by a filament of an electric bulb. Number of electrons passing through a cross-section of the filament in 16 seconds would be roughly [NCERT Exemplar Problems]

• 1020
• 1016
• 1018
• 1023

Q54: A car headlight bulb working on a 12 V car battery draws a current of 0.5 A. The resistance of the light bulb is:

• 0.5 Ω
• 6 Ω
• 12 Ω
• 24 Ω

Q55: The other name of potential difference is:

• Amphereage
• Wattage
• Voltage
• Potential energy

Q56: Keeping the potential difference constant, the resistance of a circuit is doubled. The current will become:

• Double
• Half
• One-fourth
• Four times

Q57: An electric fuse works on the:

• Chemical effect of current
• Magnetic effect of current
• Lighting effect of current
• Heating effect of current

Q58: In a filament type light bulb, most of the electric power consumed appears as:

• Visible light
• Infra-red rays
• Ultraviolet rays
• Fluorescent light