Questions · Page 3 of 4

MCQ (1 Marks)

MCQ 1011 Mark
Shivam went for buying a $CFL$ from $D -$ mart, what safety mark he should look for$?$
  • A
    Agmark
  • $ISI$ mark
  • C
    Trade mark
  • D
    Brand logo
Answer
Correct option: B.
$ISI$ mark

Shivam went for buying a $CFL$ from $D -$ mart,ISI safety mark he should look for $ISI$ mark is a certification mark for industrial products in India.
The mark certifies that a product confirms to the Indian Standard$(IS),$ mentioned as $CM/L-xxxxxxx$ on top of the mark, developed by the Bureau of Indian Standards $(BIS),$ the national standards body of India.

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MCQ 1021 Mark
A rheostat is used in an electrical circuit:
  • To change the resistance of the circuit.
  • B
    To change the potential difference.
  • C
    To change the emf.
  • D
    To change the current through a particular instrument.
Answer
Correct option: A.
To change the resistance of the circuit.
A rheostat is a variable resistor which is used to control current.
they are able to vary the resistance in circuit without interruption.
the construction of a rheostat is very similar to potentiometer.
Thus A rheostat is used in circuit to change the resistance of the circuit.
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MCQ 1031 Mark
An electric iron is based upon the principle of:
  • Heating effect of current
  • B
    Magnetic effect of current
  • C
    Chemical effect of current
  • D
    None of these
Answer
Correct option: A.
Heating effect of current
An electric iron is based on the principle of the heating effect of current.
When an electric current passes through a conductor $($like a high resistance wire$)$ the conductor becomes hot after some time and produces heat.
This is called the heating effect of current.
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MCQ 1041 Mark
Electric door bell employs:
  • A
    Permanent Magnet
  • Electromagnet
  • C
    Thermistor
  • D
    Electric bulb
Answer
Correct option: B.
Electromagnet
An electric bell is a mechanical or electronic bell that functions by means of an electromagnet.
When an electric current is applied, it produces a repetitive buzzing, clanging or ringing sound.
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MCQ 1051 Mark
What material is used for making the armature of an electric bell ? Give a reason for using this material.
  • Soft Iron
  • B
    Carbon
  • C
    Glass
  • D
    Silicon
Answer
Correct option: A.
Soft Iron
Soft iron is used for making the armature of an electric bell because we don't want the armature to retain its magnetism when the current is withdrawn.
Soft iron is magnetised easily on passing the current and completely demagnetised easily on withdrawing the current through the solenoid.
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MCQ 1061 Mark
If the number of turns in the coil of an electromagnet is more, the strength of the electromagnet will be:
  • A
    Lesser.
  • Greater.
  • C
    Double.
  • D
    Same.
Answer
Correct option: B.
Greater.
Greater.
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MCQ 1071 Mark
What does this symbol mean in electric circuits?
  • Rheostat
  • B
    Battery
  • C
    Capacitor
  • D
    Inductance
Answer
Correct option: A.
Rheostat
Rheostat is a variable resistor, which is used to control the flow of electric current by manually increasing or decreasing the resistance.
The arrow sign indicates the variability.
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MCQ 1081 Mark
A glowing filament will be:
  • A
    At a low temperature.
  • At a high temperature.
  • C
    At atmospheric temperature.
  • D
    At the temperature of ice.
Answer
Correct option: B.
At a high temperature.
At a high temperature.
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MCQ 1091 Mark
The magnetic material around the coil is wound is called:
  • A
    Magnetic substance
  • Core
  • C
    Soft iron
  • D
    None
Answer
Correct option: B.
Core
The magnetic material around the coil is wound is core.
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MCQ 1101 Mark
The bulb glows only when $.................$ flows through it.
  • Current
  • B
    Light
  • C
    Air
  • D
    Water
Answer
Correct option: A.
Current
The bulb glows only when current flows through the circuit and current heats the filament of bulb and bulb gives light.
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MCQ 1111 Mark
An electric wire connected in a circuit gets heated up when current is allowed to flow through it. This is due to:
  • Heating effect of current.
  • B
    Electrical effect of current.
  • C
    Musical effect of current.
  • D
    Optical effect of current.
Answer
Correct option: A.
Heating effect of current.
Heating effect of current.
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MCQ 1121 Mark
Which of the following equipment does not work on principle of Joule's law?
  • A
    Electric Heater
  • B
    Electric Iron
  • C
    Electric Bulb
  • Electric Fan
Answer
Correct option: D.
Electric Fan
The electric iron, electric heater and electric bulb are some of the familiar devices based on Joule’s Law, but electric fan is not based on Joule's Law.
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MCQ 1131 Mark
Given figure is a symbol of:
  • A
    Bulb
  • B
    Battery
  • Switch
  • D
    Fixed resistance
Answer
Correct option: C.
Switch
Electrical symbols of bulb, battery, switch and fixed resistance are shown in the figure.
Thus symbol shown in the question represents a switch.
A switch is used to make or break a connection in the electrical circuit.
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MCQ 1141 Mark
The magnetic effect of the current was discovered by $.................?$
  • A
    Newton.
  • B
    Joule.
  • Oersted.
  • D
    $\text{Ohm}.$
Answer
Correct option: C.
Oersted.
Oersted.
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MCQ 1151 Mark
The strength of the magnetic field due to a solenoid can be increased by:
  • A
    Decreasing the current strength in the solenoid.
  • Increasing the number of turns in the solenoid.
  • C
    By winding solenoid around a plastic rod.
  • D
    All of the above.
Answer
Correct option: B.
Increasing the number of turns in the solenoid.
Increasing the number of turns in the solenoid.
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MCQ 1161 Mark
A fan used electric current to rotate to blow:
  • Air
  • B
    Current
  • C
    Wire
  • D
    None of these
Answer
Correct option: A.
Air
A fan uses electric current to rotate to blow air.
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MCQ 1171 Mark
A battery is a combination of:
  • A
    Only single cell.
  • B
    Only two cells.
  • Two or more cells.
  • D
    None of the above.
Answer
Correct option: C.
Two or more cells.
Two or more cells.
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MCQ 1181 Mark
Match the columns:
  • A
    $1-d, 2-c, 3-b, 4-a$
  • $1-c, 2-b, 3-d, 4-a$
  • C
    $1-a, 2-c, 3-d, 4-b$
  • D
    $1-b, 2-c, 3-d, 4-a$
Answer
Correct option: B.
$1-c, 2-b, 3-d, 4-a$
 The symbol shown in option $1$ represents a load, that in option $2$ represents a heater, in option $3$ represents a bulb while in option $4$ represents a resistance.
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MCQ 1191 Mark
The heat energy produced by a glowing bulb can be minimised by using __________ bulbs in place of ordinary electric bulbs.
  • A
    A candle.
  • $CFL$ bulbs.
  • C
    Torch.
  • D
    Kerosene lamp.
Answer
Correct option: B.
$CFL$ bulbs.
$CFL$ bulbs.
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MCQ 1201 Mark
A coil of insulated currrent$-$ carrying wire wound around a piece of a magnetic substance is:
  • A
    Voltmeter
  • B
    Magnetic coil
  • Electromagnet
  • D
    None of these
Answer
Correct option: C.
Electromagnet
An electromagnet is a coil of insulated wire.
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MCQ 1211 Mark
Such a combination of two or more cells is called:
  • A
    Wire
  • B
    Cell
  • C
    Bulb
  • Battery
Answer
Correct option: D.
Battery
Combination of two or more cells is called battery.
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MCQ 1221 Mark
Which of the following is an essential element in an electric circuit?
  • A
    Switch.
  • Connecting wires.
  • C
    Voltmeter.
  • D
    Ammeter.
Answer
Correct option: B.
Connecting wires.
Connecting wires.
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MCQ 1231 Mark
What is the minimum number of cells require to make a battery?
  • A
    $5$ cells
  • $2$ cells
  • C
    $1$ cell
  • D
    $6$ cells
Answer
Correct option: B.
$2$ cells

 A combination of two or more cells is called a battery.
The minimum number of cells require to make a battery is $2.$

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MCQ 1241 Mark
Longer line in the symbol for a cell represents its $.................$ terminal.
  • Negative.
  • B
    Positive.
  • C
    Neutral.
  • D
    None of these.
Answer
Correct option: A.
Negative.
Negative.
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MCQ 1251 Mark
What does this symbol mean in electric circuit?
Image
  • $A C$ power source
  • B
    $D C$ power source
  • C
    Current generator
  • D
    None of these
Answer
Correct option: A.
$A C$ power source

 The given symbol is used for $AC$ source of electric current in an electric circuit.

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MCQ 1261 Mark
The main function of a switch is to:
  • A
    Allow charges of flow
  • Complete or break a circuit
  • C
    Make the bulb glow easily
  • D
    Prevent electric shocks
Answer
Correct option: B.
Complete or break a circuit
A switch is a device that is used for making and breaking electric current in a circuit.
It is used to turn on and turn off daily used equipment like television, washing machine, fan, light, etc.
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MCQ 1271 Mark
What is the use of flexibility strip in a doorbell?
  • It brings back striker to its original position.
  • B
    It supports the motion of the striker.
  • C
    It completes the electric circuit flexibly.
  • D
    Its a safety precaution.
Answer
Correct option: A.
It brings back striker to its original position.
It brings back striker to its original position.
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MCQ 1281 Mark
Bulbs, wires, cells and switches are known as the of a circuit.
  • Element
  • B
    Switch
  • C
    Filament
  • D
    None of these
Answer
Correct option: A.
Element
Wires, cells, switches, bulbs are element of a circuit.
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MCQ 1291 Mark
When electric current passes through a wire, it behave like a:
  • A
    Battery
  • Magnet
  • C
    Fuse
  • D
    Compass needle
Answer
Correct option: B.
Magnet
When an electric current flows through a wire, it behaves like a magnet. „
A current carrying coil of an insulated wire wrapped around a piece of iron is called an electromagnet.
The electromagnets are also used to separate magnetic material from the junk.
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MCQ 1301 Mark
Through the metal wires to the end marked $' —\ ’$ called the:
  • A
    Bulb
  • B
    Positive terminal
  • C
    Battery
  • Negative terminal
Answer
Correct option: D.
Negative terminal
The marked is called the negative terminal.
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MCQ 1311 Mark
Where can the key or switch be placed in the circuit?
  • A
    Left side of the battery.
  • B
    Right side of the battery.
  • Can be placed anywhere in the circuit.
  • D
    Near the positive terminal of the bulb.
Answer
Correct option: C.
Can be placed anywhere in the circuit.
The key or Switch can be placed anywhere in the electric circuit.
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MCQ 1321 Mark
A $........$ is used in torches.
  • A
    Generator
  • B
    Fuse
  • C
    Secondary cell
  • Dry cell
Answer
Correct option: D.
Dry cell
A common dry cell used in torches consists of a rod surrounded by a chemical paste in a metal case.
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MCQ 1331 Mark
If the coil in a simple generator is wound around a soft iron core then:
  • A
    Strength of magnetic field increases.
  • B
    Current produced will be increased.
  • C
    Voltage produced will be increased
  • All
Answer
Correct option: D.
All
Voltage$/ $current produced in a generator can be increased by:
  1. Using a powerful electromagnet to make the magnetic field stronger in place of a permanent magnet.
  2. By winding the coil round a soft iron core to increase the strength of magnetic field.
  3. By using a coil with more turns.
  4. By rotating the coil faster.
  5. By using a coil with a larger area.
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MCQ 1341 Mark
The positive terminal of one cell is connected to the:
  • A
    Positive terminal
  • Negative terminal
  • C
    Wire
  • D
    Bulb
Answer
Correct option: B.
Negative terminal
The positive terminal of one cell is connected to the negative terminal.
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MCQ 1351 Mark
An element measure the potential difference between two points in an electric circuit is:
  • Voltmeter
  • B
    Filament
  • C
    Circuit
  • D
    Ammeter
Answer
Correct option: A.
Voltmeter
The energy is transferred to the electrical components in a circuit when the charge carriers pass through them.
We use a voltmeter to measure potential difference $($or voltage$).$
The potential difference $($which is the same as voltage$)$ is equal to the amount of current multiplied by the resistance.
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MCQ 1361 Mark
Which of the following does not use magnetic effect of electric current?
  • A
    Electric fan.
  • Electric bulb.
  • C
    Electric motor.
  • D
    Refrigerator.
Answer
Correct option: B.
Electric bulb.
Electric bulb.
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MCQ 1371 Mark
Which of the following will produce maximum wastage of electricity ?
  • A
    $CFL$
  • Electric bulb
  • C
    $LED$ lights
  • D
    All are power savers
Answer
Correct option: B.
Electric bulb

The electric bulb works by heating up a small wire called the filament.
Electric current heats the filament so much that it glows.
In fact, $90\%$ of the electricity used by a electric bulb is converted to heat and this conversion produces maximum wastage of electrical energy.

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MCQ 1381 Mark
The coil of wire contained in an electric heater is known as:
  • A
    Component
  • Element
  • C
    Circuit
  • D
    Spring
Answer
Correct option: B.
Element
An electric room heater or an electric heater used for cooking contains a coil of wire.
The coil of wire used in electric heaters is called a heating element.
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MCQ 1391 Mark
Electric doorbell:
  • A
    Always consume power.
  • Consume power only when switch is pressed.
  • C
    Do not consume power practically and needs only starting power.
  • D
    Can't say.
Answer
Correct option: B.
Consume power only when switch is pressed.
When the switch is pressed, the circuit completes and ringing begins.
Hence, electrical energy is converted to sound energy.
As the switch is released, no current flows, and no energy is consumed.
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MCQ 1401 Mark
When an electric circuit from the positive terminal of the battery to the negative terminal of the battery is complete, then the circuit is said to be:
  • Closed.
  • B
    Open.
  • C
    No change.
  • D
    Disconnected.
Answer
Correct option: A.
Closed.
Closed.
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MCQ 1411 Mark
Which of the following devices can be used to break an electric circuit:
  • A
    Cell
  • B
    Bulb
  • Switch
  • D
    None of these
Answer
Correct option: C.
Switch
The switch is a simple device that is used to either break the electric circuit or to complete it.
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MCQ 1421 Mark
Which mark is necessary on electric appliances$?$
  • A
    $AGMARK$
  • $ISI$
  • C
    $FICCI$
  • D
    $KSK$
Answer
Correct option: B.
$ISI$
$ISI$ mark is the mark necessary for appliance approval.
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MCQ 1431 Mark
In electric heater:
  • A
    Chemical energy is converted to electrical energy.
  • B
    Electrical energy is converted to chemical energy.
  • Heat energy is converted to electrical energy.
  • D
    Electrical energy is converted to heat energy.
Answer
Correct option: C.
Heat energy is converted to electrical energy.
When a current passes through an electric heater, it becomes very hot and becomes a source of heat.
Therefore, in an electric heater, electrical energy is converted into heat energy.
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MCQ 1441 Mark
What does this symbol mean in electric circuit?
Image
  • Transformer
  • B
    Battery
  • C
    Capacitor
  • D
    None of these
Answer
Correct option: A.
Transformer
The given symbol is for transformer in electric circuit.
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MCQ 1451 Mark
The batteries used in tractors, trucks and inverter are also made from:
  • Cells
  • B
    Wire
  • C
    Battery
  • D
    None of these
Answer
Correct option: A.
Cells
The batteries used in tractors, trucks are also made from cells.
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MCQ 1461 Mark
The circuit breaker device which can be used in place of a fuse is called:
  • A
    $CBD$
  • $MCB$
  • C
    $MCD$
  • D
    $CBF$
Answer
Correct option: B.
$MCB$

Fuse boxes contain safety devices called fuses or circuit breakers $- MCB$ (Miniature Circuit Breaker) which are designed to prevent an excess of electric current entering your house by only allowing a certain maximum current to flow in.
When the electrical current is too large, an electromagnet attracts a spring loaded switch which breaks the circuit and cuts the power supply.
The switch must be reset before any current can flow again.

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MCQ 1471 Mark
When the switch of an electric bell is pushed.
Image
  • A
    Flow of the current stops through the electromagnet in the bell.
  • Current starts to flow through the electromagnet.
  • C
    Voltage decreases in the circuit.
  • D
    None of the above.
Answer
Correct option: B.
Current starts to flow through the electromagnet.
When the swithch of electrical bell push, circuit will complete and current will start to flow.
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MCQ 1481 Mark
Which of the following is an advantage of using electrical symbol?
  • A
    It makes the representation of electrical component easy.
  • B
    It makes the circuit drawing easier.
  • C
    It helps in solving the circuits.
  • All of the above.
Answer
Correct option: D.
All of the above.
The uses of electrical symbols are listed below:
  1. It eases the representation of an electrical component.
  2. It makes the circuit drawing easier and more compact.
  3. It gives important insights into the circuits and increases the speed of solving electrical circuits.
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MCQ 1491 Mark
The wire which melts and breaks the circuit when large current is allowed to flow through it is called.
  • A
    A fuse wire.
  • Electric wire.
  • C
    Connecting wire.
  • D
    Filament.
Answer
Correct option: B.
Electric wire.
Electric wire.
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MCQ 1501 Mark
The amount of heat produced in a wire depends on its material:
  • A
    Length
  • B
    Thickness
  • Length and thickness
  • D
    None of these
Answer
Correct option: C.
Length and thickness

Amount of heat produced in wire $= I^2R$
Where $R =$ Resistance of wire
$I =$ Current through wire
As resistance of wire $\text{R}\propto\frac{\text{L}}{\text{A}}$
So heat produced depends on Length as well as thickness.

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MCQ (1 Marks) - Page 3 - Science STD 7 Questions - Vidyadip