10th
- Imagine that you are sitting in a chamber with your back to one wall. The direction of the magnetic field is vertically downwards. The direction of current is from the front wall to the back wall because negati... 1
- When is the force experienced by a current-carrying conductor placed in a magnetic field largest? The force experienced by a current-currying conductor is the maximum when the direction of current is perpendicular to the direction of the... 1
- How does a solenoid behave like a magnet? Can you determine the north and south poles of a current-carrying solenoid A solenoid is a long coil of circular loops of insulated copper wire. Magnetic field lines are produced around the solenoid when a current i... 1
- List three sources of magnetic fields. Three sources of magnetic fields are as follows: Current-carrying conductors Permanent magnets Electromagnets 1
- (a) An electric motor converts mechanical energy into electrical energy. (a) An electric motor converts mechanical energy into electrical energy. ► False An electric motor converts electrical energy into mechanica... 1
- At the time of short circuit, the current in the circuit (a) reduces substantially Correct option is c) increases heavily 2
- The essential difference between an AC generator and a DC generator is that (a) AC generator has an electromagnet Correct option d) AC generator has slip rings while the DC generator has a commutator. 1
- The device used for producing electric current is called a (a) generator (b) galvanometer (c) ammeter (d) motor Correct option is a) generator 2
- The phenomenon of electromagnetic induction is (a) the process of charging a body (c) producing induced current in a coil due to relative motion between a magnet and the coil 1
- Which of the following correctly describes the magnetic field near a long straight wire? (a) The field consists Correct option is d) The field consists of concentric circles centred on the wire 1
- What precaution should be taken to avoid the overloading of domestic electric circuits? The precautions that should be taken to avoid the overloading of domestic circuits are as follows: Too many appliances should not be connect... 1
- An electric oven of 2 kW is operated in a domestic electric circuit (220 V) that has a current rating of 5 A. Current drawn by the electric oven can be obtained by the expression, P = VI Where, Current = I Power of the oven, P = 2 kW = 2000 W Voltage... 1
- Name two safety measures commonly used in electric circuits and appliances. Two safety measures commonly used in electric circuits and appliances are Electric Fuse: An electric fuse is connected in series it protects... 1
- A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes Correct option is c) half revolution 2
- Which sources produce alternating current? AC generators, power plants, etc., produce alternating current. 1
- Name some sources of direct current. Some sources of direct current are cell, DC generator, etc. 2
- State the principle of an electric generator. Electric generator works on the principle of electromagnetic induction. Electricity is generated by rotating a coil inside magnetic field. 1
- Explain different ways to induce current in a coil. The different ways to induce current in a coil are as follows: If a coil is moved rapidly between the two poles of a horse-shoe magnet, then... 2
- What is the role of the split ring in an electric motor? The split ring in the electric motor also known as a commutator reverses the direction of current flowing through the coil after every half... 1
- What is the principle of an electric motor? The principle of an electric motor is based on the magnetic effect of electric current. A current-carrying loop experiences a force and rota... 1
- State Fleming's left-hand rule. Fleming's left hand rule states that if we arrange the thumb, the centre finger, and the forefinger of the left hand at right angles to each... 1
- A positively-charged particle (alpha-particle) projected towards west is deflected towards north by a magnetic field. Correct option is d) upward 2
- In Activity 13.7 (page: 230), how do we think the displacement of rod AB will be affected if (i) current in rod AB The displacement of rod AB is increased due to magnetic force exerted on it, if : (i) If the current in the rod is increased then rod will b... 1
- Which of the following property of a proton can change while it moves freely in a magnetic field? Correct option is (c) velocity and (d) momentum 2