Worksheet 3 CBSE class X physics Electricity @ CBSE @NEET Exam 100 % Success

 

Important Q/A Electricity

Q. 1. If a body has positive charge, then what does it mean?

Ans: If a body has positive charge it means that it has less no. of electrons than the no. of protons. Due to this imbalance of the charges, the body will attract the negative charged body.

Q. 2. In which direction does current flow in an electric circuit?

Ans: In an electrical circuit the current flows from the positive to the negative. The conventional current always flows in the direction opposite to the direction of flow of the electron.

Q. 3. Write a low resistance device name which is always connected in series with the device through which the current is to be measured.

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Ans: Ammeter is a device that is connected in series so as to measure the current through the circuit. It has a very low resistance so that maximum current passes through it and thus the correct amount of current through the circuit can be measured.

Q. 4. Write a high resistance device name which is always connected in parallel.

Ans:
1. Voltmeter is a high resistive device that is used to measure the voltage across a component. 
2. It is always connected in parallel to the component whose voltage is to be measured. 
3. It is highly resistive so that the current cannot pass through it and thus the current will pass through the component connected in parallel to it so as to measure the accurate voltage drop across the component.

Q. 5 What does it mean a circuit is closed or open?

Ans: If a circuit is closed that means electrons can easily flow through the circuit and thus electric current will flow through it. If a circuit is open that means the electrons will not be able to flow through the circuit which means that there will be no current flowing through it.

Q. 6. IF different resistors have the same value of electric potential across them, in which way they are connected to each other?

Ans: When different resistors are connected in parallel combination the voltage drop remains the same.

Q. 7. Why, we do not use series combination of connecting electric appliances in household circuit?

Ans: We do not use series combination for connecting electrical appliances in household circuit because if there will be a short circuit in one of the appliance which led to break in the circuit will cause the working of other appliance connected in the series. Thus, Parallel combination is used for connecting electrical appliance in the household circuit.

Q. 8. What do you understand by a mixed combination of resistances?

Ans: A Mixed combination of resistances means When two more resistance are connected in series and parallel simultaneously. These type of combination are known as Mixed combination.

Q. 9. State the factors on which the heat produced in a current conductor depends. Give one practical application of this effect.

Ans: The factors on which heating effect in a current conductor depends are:
a) The time for which the current is flowing through the circuit. Greater the time greater will be the heating effect.
b) Resistance of the conductor. More resistance yields more heating effect.
c) The amount of current flowing through the circuit.
Application: This principle of heating effect of current carrying conductor is used in the iron.

Q. 10. A fuse wire consists of an alloy of lead and tin. Why?

Ans: The fuse wire is made up of lead and tin alloy as this alloy has a very low melting point and a very high resistivity. When a large amount of current flows through this alloy, due to the high resistivity heat is produced due to the flow of high current Which make the alloy melts (as it has a very low melting point). Thus, as alloy melts the circuit breaks and the appliances connected to it are saved from any damage due to the high amount of current flowing in the circuit. The iron heats up as current flows through it and thus we are able to press the clothes easily.

Ashwani Kumar

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