Class 10 Science Chapter 12 MCQ Online Test for 2020-2021
| Class: 10 | Science |
| Chapter: 12 | Electricity |
| Contents: | MCQ Online Tests with Answers and Explanation |
Class 10 Science Chapter 12 MCQ with Answers for 2020-21
Class 10 Science Chapter 12 MCQ Online Test with solutions and answers. There are more than 70 questions in the form of MCQs covering the entire chapter 12 of Class 10 Science. Most of the questions are confined to Latest NCERT Books for class 10 Science issued for session 2020-2021.
Q1
Two resistors of resistance 2Ω and 4Ω when connected to a battery will have
[A]. Same current flowing through them when connected in parallel
[B]. Same current flowing through them when connected in series
[C]. Same potential difference across them when connected in series
[D]. Different potential difference across them when connected in Parallel
Answer: Option B
Explanation:In series combination of resistances same current flows through each resistor where as in parallel combination same voltage exist across each resistor. Thus, the two resistors of resistances 2 Ω and 4 Ω are connected in series has same current flowing through it.
Q2
An electric kettle consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?
[A]. 1 A
[B]. 2 A
[C]. 4 A
[D]. 5 A
Answer: Option D
Explanation:Power = 1 Kw, In Watt, P= 1000 W
Voltage, V = 220 V
Current, I = ?
Current is given by I = P/V
I= 1000/220
I = 4.5 A
So, A fuse wire of rating slightly greater than 4.5A must be used i.e. 5A.
Q3
A cylindrical conductor of length l and uniform area of cross section A has resistance R. Another conductor of length 2l and resistance R of the same material has area of cross section
[A]. A/2
[B]. 3A/2
[C]. 2A
[D]. 3A
Answer: Option C
Explanation: In first case,
Resistivity of the conductor, ƿ = RA¹/ l
In second case,
Resistivity of the conductor, ƿ = RA¹/ 2l
Therefore, for same material, resistivity of the conductor will be same.
So, on substituting the value of ƿ in Eq. (ii), we have
RA/I = RA¹/2I = A¹ =2A
Q4
Which of the following represents voltage?
[A]. Work done/ Current x Time
[B]. Work done x Charge
[C]. Work done x Time/Current
[D]. Work done x Charge x Time
Answer: Option A
Explanation:As we know that:
W= charge × potential difference
W= Q × V
As we know that Q= I × t
Therefore, putting in above equation
W= I × t × V
V= Work done/ Current × time
Q5
What is the minimum resistance which can be made using five resistors each of 1/5 Ω?
[A]. 1/5 Ω
[B]. 1/25 Ω
[C]. 1/10 Ω
[D]. 25 Ω
Answer: Option B
Explanation:The minimum resistance is obtained when resistors are connected in parallel combination. This equivalent resistance will be:
Rƿ = R/n = 1/5/5 = 1/25 Ω
Rƿ = equivalent resistance for parallel combination.
Q6
What is the maximum resistance which can be made using five resistors each of 1/5 Ω?
[A]. 1/5 Ω
[B]. 10 Ω
[C]. 5 Ω
[D]. 1 Ω
Answer: Option D
Explanation:The maximum resistance is obtained when resistors are connected in parallel combination. This equivalent resistance will be:
Rs = n x R = 5 X 1/5 = 1Ω
Rs = equivalent resistance for series combination.
Q7
Which of the following characteristic is not suitable for a fuse wire?
[A]. Thin and short
[B]. Thick and short
[C]. Low melting point
[D]. Higher resistance than rest of wiring
Answer: Option B
Explanation:This is so because in this case, the resistance of the wire will be low.
Q8
In a quiz competition, you are asked a question where you have to choose the statement which is/ are incorrect?
[A]. In series circuit, the appliances get the same voltage as that of the power supply line.
[B]. In series circuit, all the electrical appliances have only one switch due to which they cannot be turned on or off separately.
[C]. In series circuit, if one electrical appliance stops working due to some defect, then all other appliances also stop working.
[D]. In the series connection of electrical appliances, the overall resistance of the circuit increases too much due to which the current from the power supply is low.
Answer: Option A
Explanation:In series circuit, the appliances do not get the same voltage as that of the power supply line because the voltage is shared by all the appliances. The appliances get less voltage and hence do not work properly. For example, all the bulbs connected in series do not get the same voltage of 220 volts of the power supply line. They get less voltage and hence glow less brightly.
Q9
How much energy does a 100 W electric bulb transfer in 1 minute?
[A]. 100 J
[B]. 600 J
[C]. 3600 J
[D]. 6000 J
Answer: Option D
Explanation:Energy transferred, E = power x time = 100 W x 60 s = 6000 J
Q10
The resistance of a wire of length 300 m and cross-section area 1.0 mm2 made of material of resistivity 1.0 × 10−7 Ωm is:
[A]. 2 Ω
[B]. 3 Ω
[C]. 20 Ω
[D]. 30 Ω
Answer: Option D
Explanation:Resistance, R=ρlA
Length, l = 300 m
Cross-section area, A = 1.0 mm2 = 10-6 m2
Resistivity, ρ = 1.0 × 10−7 Ωm
Resistance, R=10−7×30010−6
R = 30 Ω
What is meant by an electric circuit?
A continuous and closed path of an electric current is called an electric circuit.
What is fuse wire and how does it work?
The fuse is placed in series with the device. It consists of a piece of wire made of a metal or an alloy of appropriate melting point, for example aluminium, copper, iron, lead etc. If a current larger than the specified value flows through the circuit, the temperature of the fuse wire increases. This melts the fuse wire and breaks the circuit.
What do you know about a resistor?
A conductor having some appreciable resistance is called a resistor.
What is variable resistance or rheostat?
A component used to regulate current without changing the voltage source is called variable resistance.
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