Advertisements
Advertisements
प्रश्न
Describe one experiment to demonstrate the phenomenon of electromagnetic induction.
उत्तर
| (a) |  |
| (b) |  |
| (c) |  |
| (d) |  |
| (e) |  |
- When the magnet is stationary there is no deflection in galvanometer. The pointer read zero. [Fig. (a)]
- When the magnet with north pole facing the solenoid is moved towards the solenoid, the galvanometer shows a deflection towards the right showing that a current flows in the solenoid in the direction as shown in [Fig. (b)]
- As the motion of magnet stops, the pointer of the galvanometer comes to the zero position [Fig. (c)]. This shows that the current in the solenoid flows as long as the magnet is moving.
- If the magnet is moved away from the solenoid, the current again flows in the solenoid, but now in a direction opposite to that shown in [Fig. (b)] and therefore the pointer of the galvanometer deflects towards left [Fig. (d)].
- If the magnet is moved away rapidly i.e. with more velocity, the extent of deflection in the galvanometer increases although the direction of deflection remains the same. It shows that more current flows now.
- (vi) If the polarity of the magnet is reversed and then the magnet is brought towards the solenoid, the current in solenoid flows in the direction opposite to that shown in Fig. (b) and so the pointer of galvanometer deflect towards left [Fig. (e)].
APPEARS IN
संबंधित प्रश्न
Electric field intensity in free space at a distance ‘r’ outside the charged conducting sphere of radius ‘R’ in terms of surface charge density ‘ a ’ is............................
(a)`sigma / in_0[R/r]^2`
(b)`in_0/sigma[R/r]^2`
(c)`R/r[sigma/in_0]^2`
(d)`R/sigma[r/in_0]^2`
If ‘R’ is the radius of dees and ‘B’ be the magnetic field of induction in which positive charges (q) of mass (m) escape from the cyclotron, then its maximum speed (vmax) is _______.
A) `(qR)/(Bm)`
B)`(qm)/(Br)`
C) `(qBR)/m`
D) `m/(qBR)`
State three ways in which the strength of an electromagnet can be increased.
Explain why, the core of an electromagnet should be of soft iron and not of steel.
Write some of the important uses of electromagnets.
In which of the following case does the electromagnetic induction occur?
The current is stopped in a wire held near a loop of wire .
Draw a simple labeled diagram of a step-down transformer.
What is an electromagnet? List any two uses.
We can induce the current in a coil by ____________.
A coil of one turn is made of a wire of certain length and then from the same length, a coil of two turns is made. If the same current is passed in both the cases, then the ratio of the magnetic inductions at their centres will be:
