Electricity Class 10th notes part 2
HEATING EFFECT OF CURRENT
When electric current is passed through a high resistance wire, like nichrome wire then resistance wire becomes very hot and produce heat, this is called heating effect of current.
W = Q X V
As we know I = Q/T
Or Q = I X T
So, W = I X T X V
W = I X T X I X R
W = I2RT
Assume that electric work done converted into heat energy. Thus
H = I2RT
Short Circuit
Short-circuiting occurs when the ends of a circuit are connected by a Conductor of very low resistance as compared to that of the circuit. In household connection, short-circuiting occurs when the live (positive) Wire and the neutral (negative) wire come in direct contact with each other.
This happens due to (i) damage to the insulation of the powerline (ii) a fault in an electric appliance due to which current does not pass through it.
ELECTRIC FUSE
An electric fuse is a device which is used in series to limit the current in an electric circuit so that it easily melts due to overheating when excessive Current passes through it. A Fuse is a wire of a material with very low Melting point.
Earthing
Earthing refers to the process of transferring the immediate discharge of electrical energy directly to the earth using a low-resistance wire. This is done to ensure that in case of a short circuit or any electrical fault, the excess charge has a safe path to the ground, which helps prevent electrical shocks and protects electrical appliances.
ROLE OF MAGNETISM IN MEDICINE AND ORGANISMS
The magnetic field in our body enables us to obtain the images of its different Parts by using a technique called MRI Magnetic resonance imaging) on Analyzing the images obtained through MRI. We are able to make a medical Diagnosis, e.g. location size of a tumor in brain etc. Thus, magnetism plays an important role in modern medical science.
OVERLOADING
If too many electrical appliances of high-power rating (like electric iron, water heater etc) are switched on at the same time, they draw an extremely large current from the circuit. This condition is called overloading, and it can cause overheating of the wiring and lead to a fire. It can also happen due to an accidental hike in the supply voltage.