Magnetic Effects of Electric Current: Class 10 Science Q&A · Page 2
51 free answers on Magnetic Effects of Electric Current (Science) for Class 10 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- ScienceClass 10CBSE
Two circular coils A and B are placed closed to each other. If the current in the coil A is changed, will some current be induced in the coil B? Give reason.
When the current in coil A changes, the magnetic field associated with it also changes. As a result, the magnetic field around coil B undergoes change. The change in the magnetic field of coil B induces a current in it.
- ScienceClass 10CBSE
A coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is (i) pushed into the coil, (ii) withdrawn from inside the coil, (iii) held stationary inside the coil?
Solution: (i) When a bar magnet is pushed into the coil, a current is induced in the coil momentarily. As a result, the galvanometer deflects in a particular direction momentarily. (ii) When the bar magnet is withdrawn from inside the coil, a current is induced momentarily but in the opposite direction, and the galvanometer deflects in the opposite direction momentarily. (iii) When the bar magnet is held stationary inside the coil, no current will be induced. As a resu
- ScienceClass 10CBSE
Name some devices in which electric motors are used.
Solution: A few devices in which electric motors are used are: Electric fans Water pumps Mixers Washing machines
- ScienceClass 10CBSE
Imagine that you are sitting in a chamber with your back to one wall. An electron beam, moving horizontally from back wall towards the front wall, is deflected by a strong magnetic field to your right side. What is the direction of magnetic field?
Solution: The direction of the magnetic field can be determined using Fleming’s Left-hand rule. The direction of the magnetic field will be perpendicular to the direction of the current and the direction of deflection, i.e., either upward or downward. The direction of the current is from the front wall to the back wall because negatively charged electrons move from the back wall to the front wall. The direction of the magnetic force is rightward. Hence, using Fleming’s lef
- ScienceClass 10CBSE
When is the force experienced by a current–carrying conductor placed in a magnetic field largest?
Solution: When the direction of the current is perpendicular to the direction of the magnetic field, the force experienced is the largest.
- ScienceClass 10CBSE
List two methods of producing magnetic fields.
Solution: Following are the methods of producing magnetic fields: By using a permanent magnet, we can produce a magnetic field, and it can be visualized by spreading iron fillings on white paper and keeping a magnet beneath the paper. A current-carrying straight conductor produces magnetic field. Different types of conductors, such as solenoid and circular loops, can be used to see the presence of a magnetic field.
- ScienceClass 10CBSE
State whether the following statements are true or false. 1. An electric motor converts mechanical energy into electrical energy. 2. An electric generator works on the principle of electromagnetic induction. 3. The field at the center of a long circular coil carrying current will be parallel straight lines. 4. A wire with a green insulation is usually the live wire of an electric supply.
Solution: False An electric motor converts electrical energy into mechanical energy. True An electric generator is a device that generates electricity by rotating a coil in a magnetic field. True A long circular coil is a solenoid. The magnetic field lines inside a solenoid are parallel straight lines. False Live wires have red insulation co
- ScienceClass 10CBSE
At the time of short circuit, the current in the circuit 1. reduces substantially. 2. does not change. 3. increases heavily. 4. vary continuously.
increases heavily When two naked wires in the circuit come in contact with each other, the amount of current flowing in the circuit increase abruptly resulting in short circuit.
- ScienceClass 10CBSE
The essential difference between an AC generator and a DC generator is that AC generator has an electromagnet while a DC generator has permanent magnet. DC generator will generate a higher voltage. AC generator will generate a higher voltage. AC generator has slip rings while the DC generator has a commutator.
Solution: AC generator has slip rings, while the DC generator has a commutator. AC generators have two rings known as the slip rings, while DC generators have two half rings known as the commutator. This is the main difference between AC generator and DC generator.
- ScienceClass 10CBSE
The device used for producing electric current is called a 1. generator 2. galvanometer 3. ammeter 4. motor
Solution: generator The device used for producing electric current is known as a generator. The generator converts mechanical energy to electric energy.
- ScienceClass 10CBSE
The phenomenon of electromagnetic induction is 1. the process of charging a body. 2. the process of generating a magnetic field due to a current passing through a coil. 3. producing induced current in a coil due to relative motion between a magnet and the coil. 4. the process of rotating a coil of an electric motor.
producing induced current in a coil due to relative motion between a magnet and the coil. The phenomenon of inducing current in a coil due to the relative motion between the coil and the magnet is known as electromagnetic induction.
- ScienceClass 10CBSE
Which of the following correctly describes the magnetic field near a long straight wire? 1. The field consists of straight lines perpendicular to the wire. 2. The field consists of straight lines parallel to the wire. 3. The field consists of radial lines originating from the wire. 4. The field consists of concentric circles centered on the wire.
Solution: The field consists of concentric circles centred on the wire. The magnetic field near a long straight wire is concentric circles. Their centres lie on the wire.
- ScienceClass 10CBSE
What precaution should be taken to avoid the overloading of domestic electric circuits?
Solution: A few of the precautions to be taken to avoid the overloading of domestic electric circuits are as follows: Connecting too many devices to a single socket should be avoided Using too many appliances at the same time should be avoided Faulty appliances should not be connected to the circuit
- ScienceClass 10CBSE
An electric oven of 2 kW power rating is operated in a domestic electric circuit (220 V) that has a current rating of 5 A. What result do you expect? Explain.
Solution: The current drawn by the electric oven can be calculated using the formula P = V × I I = P/V Substituting the values, we get I = 2000 W/220 V = 9.09 A The current drawn by the electric oven is 9.09 A which exceeds the safe limit of the circuit. This causes the fuse to melt and break the circuit.
- ScienceClass 10CBSE
Name two safety measures commonly used in electric circuits and appliances.
Solution: The safety measures commonly used in electric circuits are as follows: Fuse Each circuit should be connected to a fuse because a fuse prevents the flow of excessive current through the circuit. When the current in the circuit exceeds the maximum limit of the fuse element, the fuse melts to stop the flow of current protecting the appliance connected to the circuit. Earthing Earthin
- ScienceClass 10CBSE
Choose the correct option. A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each 1. two revolutions 2. one revolution 3. half revolution 4. one-fourth revolution
Solution: half revolution When a rectangular coil is rotated in a magnetic field, the direction of the induced current changes once in a half revolution; as a result, the direction of the current in the coil remains the same.
- ScienceClass 10CBSE
Which sources produce alternating current?
Power plants and AC generators are some of the sources that produce alternating current.
- ScienceClass 10CBSE
Name some sources of direct current.
Solution: DC generators and cells are some sources of direct current.
- ScienceClass 10CBSE
State the principle of an electric generator.
An electric generator works on the principle of electromagnetic induction. In a generator, electricity is generated by rotating a coil in the magnetic field.
- ScienceClass 10CBSE
Explain different ways to induce current in a coil.
Solution: Following are the different ways to induce a current in a coil: If the coil is moved rapidly between the two poles of a horseshoe magnet, an electric current is induced in the coil. When a magnet is moved relative to the coil, an electric current is induced in the coil.