## Extra Questions of Class 10 Science Chapter 13 Magnetic Effects of Electric Current PDF Download

We have provided you with Extra and Important Questions from Class 10 Science Chapter 13 Magnetic Effects of Electric Current. This Extra and Important Questions will help you to score 100% in your Board Exams. These extra questions will be helpful to revise the important topics and concepts.

# Magnetic Effects of Electric Current Class 10 Important Questions with Answers Science Chapter 13

## Extra Questions for Class 10 Science Chapter 13 Very Short Answer Type

Question: Name the type of current:

(a) used in household supply. (b) given by a cell.

Answer: (a) Alternating current. (b) Direct current.

Question: Name the physical quantities which are indicated by the direction of thumb and forefinger in the Fleming’s right hand rule?

Answer: In Fleming’s right hand rule, thumb indicates — direction of motion of the conductor; forefinger indicates — direction of magnetic field.

Question: What is meant by the term ‘frequency of an alternating current’?

Answer: Frequency of Alternating current is equal to the number of cycles completed in one second. In India, frequency of AC is 50 Hz i.e. 50 cycles per second.

Question: The given magnet is divided into three parts A, B, and C.Name the parts where the strength of the magnetic field is: (i) maximum (ii) minimum.

How will the density of magnetic field lines differ at these parts?

Answer: (i) Maximum strength – at A and C. (ii) Minimum strength – at B

At A and C, magnetic field lines are crowded while at B, they are spread out

Question: Define magnetic effect of electric current.

Answer: The production of magnetic field around a conductor when electric current is passed through it.

Question: What is fuse?

Answer: Fuse is the most important safety device, used for protecting the circuits due to short-circuiting or overloading of the circuits.

Question: What is the pattern of magnetic field around a current carrying conductor?

Answer:The magnetic field around a current carrying conductors forms a pattern of concentric circles.

Question: Draw an appropriate schematic diagram showing common domestic circuits and discuss the importance of fuse.

Question: What is electric motor?

Answer: Electric motor: An electric motor is a rotating device that converts electrical energy to mechanical energy.

Question: Write down principle of working of electric motor?

Answer: Principle: A current-carrying conductor when placed in a magnetic field experiences a force.

Question: What is galvanometer?

Answer: A galvanometer is an instrument that can detect the presence of a current in a circuit.

## Extra Questions for Class 10 Science Chapter 13 Short Answer Type

Question: Describe domestic electric circuits.

Answer: Domestic Electric circuits: In our houses, we receive AC electric power of 220 V with a frequency of 50 Hz. One of the wires in this supply is with red insulation, called live wire. The other one is of black insulation, which is a neutral wire. The potential difference between the two is 220 V.The third is the earth wire that has green insulation and this is connected to a metallic body deep inside the earth. It is used as a safety measure to ensure that any leakage of current to a metallic body of an appliance does not give any severe shock to the user.

Question: What will happen if a current carrying conductor is placed in magnetic field? How can the direction of magnetic field be found out?

Answer: A current-carrying conductor when placed in a magnetic field experiences a force.

If the direction of the field and that of the current are mutually perpendicular to each other, then the force acting on the conductor will be perpendicular to both as given by Fleming’s left-hand rule.

Question: What does the direction of thumb indicate in the right-hand thumb rule? In what ways this rule is different from Fleming’s left-hand rule?

Answer: The thumb indicates the direction of current in the straight conductor held by curled fingers, whereas Fleming’s left-hand rule gives the direction of force experienced by current carrying conductor placed in an external magnetic field.

Question: What is the difference between a direct current and an alternating current? How many times does AC used in India change direction in one second?

Answer: Direct current always flows in one direction but the alternating current reverses its direction periodically. The frequency of AC in India is 50 Hz and in each cycle it alters direction twice. Therefore, AC changes direction 2 × 50 = 100 times in one second.

Question: What is the role of fuse, used in series with any electrical appliance? Why should a fuse with defined rating not be replaced by one with larger rating?

Answer: Fuse is used for protecting appliances due to short-circuiting or overloading. The fuse is rated for a certain maximum current and blows off when a current more than the rated value flows through it. If a fuse is replaced by one with larger ratings, the appliances may get damaged while the protecting fuse does not burn off. This practice of using fuse of improper rating should always be avoided.

Question: On which factors does the magnetic field produced by a current carrying conductor at a given point depend?

Answer: The magnetic field produced by a given current decreases as the distance from it increases.The magnitude of the magnetic field produced at a given point increases as the current through the wire increases.

Question: What is electric generator? Write down its principle of working.

Answer: Electric Generator: A generator converts mechanical energy into electrical energy.

Principle: It works on the basis of electromagnetic induction. AC generator produces AC current and DC generator produces DC current.

Question: What is difference between AC and DC? Write down advantage of AC over DC?

Answer: The difference between the direct and alternating currents is that the direct current always flows in one direction, whereas the alternating current reverses its direction periodically.

In India, the AC changes direction after every 1/100 second, that is, the frequency of AC is 50 Hz. An important advantage of AC over DC is that electric power can be transmitted over long distances without much loss of energy.

Question: With the help of a labelled circuit diagram illustrate the pattern of field lines of the magnetic field around a current carrying straight long conducting wire. How is the right hand thumb rule useful to find direction of magnetic field associated with a current carrying conductor?

Answer: Right hand thumb rule states that if a current carrying straight conductor is held in the right hand with the thumb pointing towards the direction of current, then the fingers will wrap around the conductor in the direction of the field lines of the magnetic field.

Question: Describe the activity that shows that a current-carrying conductor experiences a force perpendicular to its length and the external magnetic field.

• Take a small aluminium rod AB (of about 5 cm).
• Using two connecting wires, suspend it horizontally from a stand.
• Place a strong horse-shoe magnet in such a way that the rod lies between the two poles with the magnetic field directed upwards. For this put the north pole of the magnet vertically below and south pole vertically above the aluminium rod.
• Connect the aluminium rod in series with a battery, a key and a rheostat.
• Now pass a current through the aluminium rod from end B to end A.
• It is observed that the rod is displaced towards the left. You will notice that the rod gets displaced.
• Reverse the direction of current flowing through the rod and observe the direction of its displacement. It is now towards the right.

The displacement of the rod in the above activity suggests that a force is exerted on the current-carrying aluminium rod when it is placed in a magnetic field.

## Extra Questions for Class 10 Science Chapter 13 Long Answer Type

Question: Write down a short note on magnetic field produced by a solenoid.

Answer: Magnetic field due to a solenoid

Solenoid: A coil of many circular turns of insulated copper wire wrapped closely in the shape of a cylinder is called a solenoid.

• The pattern of the magnetic field around a current carrying solenoid is same as that of a bar magnet. One end of the solenoid behaves as a magnetic North pole, while the other behaves as a South pole.
• The field lines inside the solenoid are in the form of parallel straight lines.
• The field is uniform inside the solenoid.
• A strong magnetic field produced inside a solenoid can be used to magnetise a piece of magnetic material, like soft iron, when placed inside the coil. The magnet so formed is called an electromagnet.

Question: Describe the magnetic field produced due to current-carrying circular loop.Magnetic field due to current-carrying circular loop

• At the centre of the current carrying loop the magnetic field appears to be a straight line.
• The magnetic field produced by a current carrying wire at a given point depends directly on current passing through it.

Question: AB is a current carrying conductor in the plane of the paper as shown in the Figure. What are the directions of magnetic fields produced by it at points P and Q? Given r1 > r2, where will the strength of the magnetic field be larger?

Answer:Into the plane of paper at P and out of it at Q. The strength of the magnetic field is larger at the point located closer i.e., at Q.

Question: Why does a magnetic compass needle pointing North and South in the absence of a nearby magnet get deflected when a bar magnet or a current carrying loop is brought near it. Describe some salient features of magnetic lines of field concept.

Answer: Current carrying loops behave like bar magnets and both have their associated lines of field. This modifies the already existing earth’s magnetic field and a deflection results. Magnetic field has both direction and magnitude. Magnetic field lines emerge from N – pole and enter S – pole. The magnetic field strength is represented diagrammatically by the degree of closeness of the field lines.

Field lines cannot cross each other as two values of net field at a single point cannot exist. Only one value, a unique net value, can exist. If in a given region, lines of field are shown to be parallel and equispaced, the field is understood to be uniform.

Question: State the consequences that can lead to a short circuit. (or)

One of the major cause of fire in office building is short circuiting. List three factors which may lead to the short circuit.

Answer: It occurs as a consequence of

• failure of electrical insulation’s due to which live wire comes in direct contact with neutral or earth wire.
• presence of external conducting material such as water which is introduced accidentally into the circuit.
• electrical appliances are forced to operate when its moving parts are jammed.
• connection of current carrying parts of electrical equipment’s comes in contact to one another due to human or natural cause and use of less rating wires.
• when this happens, there is an excessive electric current which can damage the circuit and may also cause electrical fires.