Effect of electric current
Answers
ᴀɴ ᴇʟᴇᴄᴛʀɪᴄ ᴄᴜʀʀᴇɴᴛ ɪs ᴛʜᴇ ʀᴀᴛᴇ ᴏғ ғʟᴏᴡ ᴏғ ᴇʟᴇᴄᴛʀɪᴄ ᴄʜᴀʀɢᴇ ᴘᴀsᴛ ᴀ ᴘᴏɪɴᴛ2622 ᴏʀ ʀᴇɢɪᴏɴ.614 ᴀɴ ᴇʟᴇᴄᴛʀɪᴄ ᴄᴜʀʀᴇɴᴛ ɪs sᴀɪᴅ ᴛᴏ ᴇxɪsᴛ ᴡʜᴇɴ ᴛʜᴇʀᴇ ɪs ᴀ ɴᴇᴛ ғʟᴏᴡ ᴏғ ᴇʟᴇᴄᴛʀɪᴄ ᴄʜᴀʀɢᴇ ᴛʜʀᴏᴜɢʜ ᴀ ʀᴇɢɪᴏɴ.832 ɪɴ ᴇʟᴇᴄᴛʀɪᴄ ᴄɪʀᴄᴜɪᴛs ᴛʜɪs ᴄʜᴀʀɢᴇ ɪs ᴏғᴛᴇɴ ᴄᴀʀʀɪᴇᴅ ʙʏ ᴇʟᴇᴄᴛʀᴏɴs ᴍᴏᴠɪɴɢ ᴛʜʀᴏᴜɢʜ ᴀ ᴡɪʀᴇ. ɪᴛ ᴄᴀɴ ᴀʟsᴏ ʙᴇ ᴄᴀʀʀɪᴇᴅ ʙʏ ɪᴏɴs ɪɴ ᴀɴ ᴇʟᴇᴄᴛʀᴏʟʏᴛᴇ, ᴏʀ ʙʏ ʙᴏᴛʜ ɪᴏɴs ᴀɴᴅ ᴇʟᴇᴄᴛʀᴏɴs sᴜᴄʜ ᴀs ɪɴ ᴀɴ ɪᴏɴɪᴢᴇᴅ ɢᴀs (ᴘʟᴀsᴍᴀ).
Answer:
Electric current is the flow of electrons in a circuit. To make it easier to understand, imagine water flowing through a pipe. The water flowing through pipes is similar to electrons flowing through wires. Let ‘I’ denote the current which is measured in Ampere which is equivalent to the flow of one coulomb per second (6.241 x 1018 electrons).
When we switch on a light bulb, it is due to the heating effect of electric current, and when we turn the ceiling fan on, it is due to the magnetic effect of current. Let us learn more about the heating and magnetic effects of electric current.
Heating Effects of Electric Current
The fundamental law of conservation of energy states that the total energy in an isolated system is always constant. It means that energy can neither be created nor destroyed – it can only be transferred from one form to the other.
To understand this, take a look at this example. When we line up a row of dominoes and tip over the first piece, it results in a chain reaction which causes them to fall. This happens because the mechanical energy of the first domino is transferred to the mechanical energy of the next domino and so on. And the energy remains mechanical, as it is passed on from one domino unto another.
How does it work?
An electric current is passing through a conductor which becomes hot after some time and produces heat. This is due to the conversion of some of the electrical energy that passes through the conductor, into heat energy. This effect of electric current is called the heating effect of current.
Mathematical Expression of Heat Produced
When a unit charge moves from one point to the other, some work is required to do so. The potential difference is the measure of work that is done in moving the charge across the circuit. Current in a circuit is equal to the amount of charge flowing in one second.
Therefore, work that is done in moving charge ‘Q’ through a potential difference ‘V’ in time ‘t’ is given by
Workdone = potential difference × current × time
W = VIt
Using ohm’s law, we know
V = IR
Therefore work can also be expressed as
W = (IR) It = I2Rt
Thus, we can say that the heat produced is directly proportional to resistance, to time and the square of the current.
Some applications of the Heating Effect
When you are late for work or for a date, you need to iron your shirt; you reach over for the iron. This is the most basic example of the heating effect.
In a microwave oven, electric energy is converted into heat which gives us some of the most delicious food and desserts to eat.
When girls find it hard to tame their hair, they turn to their hair curler or straightener. When you touch your hair, it feels warm to the touch. Well, it’s because it works on the same principle.
Explanation:
Magnetic Effects of Electric Current
Let us set up a simple electric circuit consisting of a wire, a battery, a switch and a bulb. When current passes through the circuit, the bulb lights up. Now try bringing a magnetic compass near the circuit and notice how the needle deflects when the circuit is complete.
These effects are called the magnetic effects of electric current and they occur because they experience a force. The first scientist who showed that electric current also produces magnetic effect was Hans Christian Oersted.
The direction of the force depends on the direction of the current that flows through the conductor. You can find the direction with the simple right-hand rule, which states that: the index finger points in the direction of velocity ‘v’, middle finger points to the direction of magnetic field ‘B’ and the thumb points in the direction of the cross product ‘F’. The magnetic field can be denoted by
F⃗ =qv⃗ ×B⃗
A magnetic field is formed around a conductor when current flows through it which means it acts like a magnet. We also know that in magnets, unlike poles attract and like poles repel each other.
We know that in magnets like poles repel and unlike poles attract each other, so depending on the direction of the magnetic field induced, the conductor will either get attracted to or get repelled by the permanent magnet.