Electric Current class 10 Mcq's

Electric -Current  (Q.1)  Direction of conventional current is from

(a) Negative terminal to positive terminal
(b) Positive terminal to negative terminal
(c) In any direction
(d) In both the directions
 

(Q.2)  Electric current is defined as the

(a) Rate of flow of charges
(b) Total quantity of charges flowing through the circuit.
(c) Number of electrons flowing through the circuit.
(d) Number of ions flowing

 

(Q.3)  S.I. Unit of current is

(a) Ampere
(b) Coulomb
(c) Volt
(d) Watt
 

(Q.4)  Potential difference is defined as

(a) The amount of work done in moving a unit charge in a unit time
(b) Distance between two terminals
(c) Length of the connecting wire
(d) The amount of work done in moving a unit charge from one point to another.

 

(Q.5)  S.I. Unit of potential difference is

(a) Volt
(b) Coulomb
(c) Ampere
(d) Watt
 

(Q.6)  1 microampere is equivalent to

(a) 6.25 x 10⁹ electrons
(b) 6.25 x 10⁶ electrons
(c) 6.25 x 10¹² electrons
(d) 6.25 electrons
 

(Q.7)  The length of a wire is doubled, but its cross section remains the same, then its resistance will become

(a) 4 times
(b) 2 times
(c) ½ times
(d) 8 times
 

(Q.8)  Resistance of a conductor do not depends upon

(a) The length of the conductor
(b) Area of cross section of the conductor
(c) Material of the conductor
(d) Temperature of the conductor

 

(Q.9)  According to Ohm’s law

(a) Current is directly proportional to the potential difference
(b) Current is inversely proportional to the potential difference
(c) Current is equal to the potential difference
(d) Current is independent of potential difference

 

(Q.10)  Heat produced due to flow of current through a conductor is given by the formula

(a) H = I² R t
(b) H = V I/ t
(c) H = V t / R
(d) H= It

 

(Q.11)  1volt=

(a) 1joule/1newton

(b) 1joule/1cm
(c) 1joule/1coulomb
(d) 1newton/1metre
 

(Q.12)  The combined resistance of any number of resistances connected in series is equal to

(a) The sum of individual resistances
(b) The sum of reciprocals of individual resistances
(c) Product of individual resistances
(d) Highest individual resistance
 

(Q.13)  The reciprocal of the combined resistance of any number of resistances connected in parallel is equal to

(a) The sum of reciprocals of individual resistances
(b) Reciprocal of the product of individual resistances
(c) Reciprocal of sum of all the resistances
(d) Sum of individual resistances

 

(Q.14)  When two or more resistors are connected in series

(a) The current passing through each resistor is same
(b) The potential difference across each resistor is same
(c) Current is inversely proportional to the potential difference

(d) Potential difference and current are independent

 

(Q.15)  When two or more resistors are connected in parallel

(a) The current passing through each resistor is same
(b) The potential difference across each resistor is same
(c) Current and potential are inversely proportional

(d) Current increases linearly

 

(Q.16)  Commercial unit of electrical energy is

(a) Joule
(b) Coulomb
(c) Watt
(d) k W h
 

(Q.17)  The work done in moving a charge of 3 C across two points having potential difference 20V

(a) 40J
(b) 60J
(c) 80J
(d) 100J
 

(Q.18)  Power rating of an electric appliance indicates

(a) The rate of consumption of electrical energy.
(b) Amount of heat evolved.
(c) Brightness of the light.
(d) Quality of the appliance.
 

(Q.19)  One kilowatt hour =

(a) 3.6 x 10⁶ J
(b) 3.6 kJ
(c) 1000 watt
(d) 3.6 x 10⁶ calories
 

(Q.20)  What happens to the heating effect when the direction of current is reversed?

(a) Cooling effect is observed
(b) Amount of heat remains unchanged
(c) There will be a short circuit
(d) Current will increase suddenly

 

(Q.21)  Alloys are usually used in electrical heating devices because

(a) Resistivity of an alloy is generally higher than that of constituent elements.
(b) Alloys oxidizes readily at high temperature.
(c) Alloys are bad conductor of heat

(d) Alloys do not have free electrons

 

(Q.22)  An electric bulb of 40 W is connected to a source of 220 V, the current drawn by the bulb will be

(a) 0.18 A
(b) 18 A
(c) 1.8 A
(d) 180 A
 

(Q.23)  Electrical energy consumed in lighting an electrical bulb of 60 W for 5 hours is

(a) 3 kWh
(b) 1.08 x 10⁶ J
(c) 5KWh
(d) 2.03 x 10⁶ J

 

(Q.24)  What is the melting point of tungsten?

(a) 3050⁰C
(b) 3578⁰C
(c) 3380⁰C
(d) 3850⁰C
 

(Q.25)  Difference of electric pressure is called:

(a) Electric difference
(b) Potential difference
(c) Charge difference
(d) Volt difference
 

(Q.26)  An electric iron consumes energy at a rate of 840W when it is connected to a source of voltage 220V. The current flowing is

(a) 3.81A
(b) 3A
(c) 2A
(d) 1.4A
 

(Q.27)  What is the minimum resistance that can be obtained using three 5 ohm resistors?

(a) 5 ohm
(b) 1.6 ohm
(c) 15 ohm
(d) 1 ohm
 

(Q.28)  A refrigerator rated 400W operates 8hour per day. The total number of commercial units for 30days will be

(a) 96
(b) 46
(c) 36
(d) 100

(Q.29)  A 100 watt electric bulb is lighted for 2 hours daily and four 40 watt bulbs are lighted for 4 hours daily. Calculate the electric energy consumed in kwh in 30 days.

Q.30)  Two lamps, one rated 100 W at 220 volts and the other 60W at 220 volts are connected in parallel to a 220 V supply. What current is drawn from the supply line?

(Q.31)  Calculate the amount of charge that would flow in 1 hour through the elements of an electric bulb drawing a current of 0.4 A.