Q1. _______ is used for electrical measurements.
Galvanometer is used for electrical measurements.
Updated on: 2026-03-31 | Author: Rahul Patil
Galvanometer is used for electrical measurements.
A coil of an alloy nichrome is used in electric heater cooker as a resistor.
Alternating current : oscillatory :: Direct current : non-oscillatory
Electric energy consumed by iron in 7200 s is
Thus, total energy consumed in the month of April,
We know,
1 unit =\[ 3 . 6 \times {10}^6 J\]
or, \[1 J = \frac{1}{3 . 6 \times {10}^6} \] unit
Thus,
\[237600000 J = \frac{237600000}{3 . 6 \times 1000000} = 66\] units
| Direct current | Alternating current | |
| 1. | Magnitude of direct current from a source remains the same. i.e., nonoscillatory. | Alternating current varies in magnitude continuously. i.e., oscillatory. |
| 2. | Direction remains the same. | Direction reverses periodically, i.e., after equal intervals of time. |
| 3. | This type of current is not used much for household purposes but used in batteries, torches, etc. | This type of current is used in electrical household appliances such as electric heater, refrigerators, electric irons, etc. |
| 4. | Frequency of D.C. is zero. | Frequency of A.C. in India is 50 Hz, i.e., its cycle changes in `1/50` second. |
| 5. | Produced by D.C. generator. | Produced by A.C. generator. |
Electric motor : converts electrical energy into mechanical energy : : Electric generator : converts mechanical energy into electrical energy
Electric motors are devices that convert electrical energy into mechanical energy- Right
Fuse is an important application of heating effect of electric current used in electric circuits.
It protects circuits and appliances by stopping the flow of any excess electric current.
If a current larger than the specific value flows through the circuit, the temperature of fuse wire increases. This melts the fuse wire and breaks the circuit.
In summer season, when consumption of electrical power is huge in the evening due to home lighting, fan, air conditioner, use of electricity in shops etc, an excessive current is drawn from the transformer. If the capacity of the transformer is insufficient, its fuse wire melts, and the supply gets shut down.
Electric bell
Explanation-
Others are used to generate heat energy when it becomes hot whereas electric bell do not produce any heat energy.
Nichrome
Explanation-
Nichrome is an alloy used for making wires, while others are soft metals.
Temperature
Explanation-
Temperature is a degree of hotness while conduction, convection, and radiation are modes of heat transfer.
Fleming's left hand rule : electric current : : Fleming's right hand rule : direction of induced current
Galvanometers are used for electrical measurements- Right
Copper and aluminium are excellent electrical conductors.
Since the resistance of copper and aluminium is very low, the amount of heat generated while carrying an electric current through them is also low.
The electric bulb operates under the principle of the heating effect of electric current.
The bulb's solenoid-type coil has a very high melting point and high resistance.
The solenoid-type coil of the lightbulb becomes heated to a high temperature (up to 3400°C) and begins to shine when current is delivered through it.
As a result, tungsten metal creates a solenoid-type coil in an electric bulb.
For practical applications, devices consuming high electrical power are used over a period of time.
This leads to heavy expenditure of electrical energy. To measure such value of energy unit joule is significantly small.
Overloading in the electric circuit can be avoided by not connecting many electric appliances at a time in the circuit.
The household electrical connections mainly consist of live, neutral and earth wires.
The potential difference between live and neutral wires is around 220 V.
Sometimes, due to fault in the electrical appliances or damage of the insulating coating around the two wires i.e., neutral and live, the two wires come in contact with each other and large current flows through them causing short circuit.
Large amount of heat is produced due to flow of this large current. Any inflammable material like wood, plastic, cloth, etc. present around the short-circuited place can catch fire.
The potential difference between live and neutral wires is around 220 V.
In an electric bulb, coil of tungsten metal is used.
Appliances that uses electric motor are Dryers, vacuum cleaners, fans, air conditioners, refrigerators, freezers, etc.
Increasing the current passing through the wire decreases the magnetic field intensity- Wrong
Live wire and neutral wires have a 220 V potential difference- Right
| Column A | Column B |
| 1) Direct current | b) Non oscillatory |
| 2) Alternating current | a) Oscillatory |
Fuse wire, electric iron, electric bulb, electric cooker, geyser.
Ammeter, microphone, electric bell, galvanometer, loud speaker, electric generator, electric motor, telephone receiver, radio, stereo speaker.
Electrical appliances used in homes like geyser, heater, motor, oven, washing machine, etc. have high power consumption.
If such appliances are connected simultaneously, a large amount of current flows in the circuit.
This current may exceed permissible value and cause overloading.
The figure shows the construction of electric motor.
Principle of an electric motor: Electric motor works on the principle that a current-carrying conductor placed in a magnetic field experiences a force.
Electric motor is used in fans, washing machines, fax machines etc.
The figure shows the construction of an electric generator.
Principle of electric generator: Electric generator works on the principle of electromagnetic induction. When the coil of the electric generator rotates in a magnetic field, the magnetic field induces a current in this coil. This induced current then flows into the circuit connected to the coil.
Uses of electric generator are-
Providing backup energy for emergencies.
Powering construction sites.
Powering nuclear reactor plants.
Providing backup for hospitals and other office buildings
Generator
Explanation:
Others restrict flow of current while generator is used to produce current.
Magnet
Explanation:
Others devices are based on the phenomenon of electromagnetism while the magnet is not.
The alternating current is an oscillatory current- Right
The electricity bill specifies the usage in unit.
The frequency of AC is 50 Hz.
The frequency of the alternating current is 50 Hz- Right
The ‘live’ and the ‘neutral’ wires have potential difference of 220 V.
The right-hand thumb rule is also called Maxwell’s cork- screw rule.
The unit of electrical power is watt.
Explanation:
These days when current in the circuit suddenly increases MCB switches are used.
Due to overloading, fuse wire melts and the supply gets shut down.
Due to a fault in the equipment or if the plastic coating on the ‘live’ and the ‘neutral’ wires gives away the two wires come in contact with each other and a large current flows through it producing heat. This is known as short circuit.
A solenoid is a copper wire with a resistive coating coiled into a chain of loops. When an electric current flows through a solenoid, magnetic lines of force form in a pattern. Solenoid magnetic fields are similar to those created by bar magnets.
A solenoid's open ends function as magnetic north and south poles, respectively.
Electric motor is a device which converts electrical energy into mechanical energy.
An oxidising agent is a reactant which readily transfers oxygen atoms to another substance by reducing itself in the process.
When consumption of electrical power is huge, excessive current is drawn from the transformer supplying the electricity, and if the capacity of the transformer is insufficient, its fuse wire melts and the supply gets shutdown. Such events as called as overloading.
When a resistor is connected in an electrical circuit, heat is produced in it due to the current. This is known as the heating effect of current.
The potential difference is the difference in the electric potential of two different points.
Earthing wire is used to protect one from an electric shock.
It does this by providing a path for a fault current to flow to the earth.
It also causes the protective device (fuse) to switch off the electric current to the circuit that has the fault.
Nowadays, Miniature Circuit Breakers (MCB) is used to turn off the sudden increase in current in the electrical circuit of the house.
Overloading occurs, when more appliances work together in a circuit.
Tungsten metal is used to make the filament of an electric bulb.
Michael Faraday
Ice
= 720 × 103 J
Comparing E1 and E2, E1 > E2
The energy consumed by the T.V. set is more than that consumed by the heater.
A galvanometer is a sensitive device that works on the principle that a current-carrying conductor placed in a magnetic field experiences a force.
The pointer on the galvanometer dial is connected to a coil.
The coil is placed between the pole pieces of a magnet such that, when small current flows through the coil, the rotation of the coil will be proportional to the current.
In galvanometer, the pointer deflects on both sides of the zero mark depending on the direction of the current.
A galvanometer is used for detecting and measuring electric current.
Stretch the index finger, the middle finger, and the thumb of the left hand mutually perpendicular to each other. If the index finger is in the direction of the magnetic field and the middle finger points in the direction of the current, then the thumb will point towards the direction of the force on the conductor.
The electric heater-cooker works on the principle of heating effect of electric current.
Alloys (such as nichrome) as compared to metals have higher resistivity.
Unlike metals they can be heated to higher temperature.
There is minimum power loss, when electrical energy is carried over long distances in the form of AC.
Fuse wire, electric iron, electric bulb, electric cooker, geyser.