P-1 Effects of electric current Science - P-1 Effects of electric current

Observe the following diagram and choose the correct alternative: (March 2019)

Write the correct option by observing the figures.

Electromagnetic induction means

If 220 V potential difference is applied across an electric bulb, a current of 0.45 A flows in the bulb. What must be the power of the bulb?

The resistance of a wire is 100 Ω. If it carries a current of 1A for 10 seconds, the heat produced will be……….

State one advantage of AC over DC.

What is the periodic time of AC in India?

State Faraday’s law of induction.

What is the value of frequency of AC in India?

What is the value of frequency of AC in India?

In practice the unit kWh is used for the measurement of electric energy, rather than the joule.

For electric power transmission, copper or aluminium wire is used.

 In the electric equipment producing heat e.g. iron, electric heater, boiler, toaster, etc. an alloy such as Nichrome is used, not pure metals.

Tungsten is used to make a solenoid type coil in an electric bulb.

Iron is a conductor of electricity, but when we pick up a piece of iron resting on the ground, why don't we get electric shock?

State the principle on which the working of an electric motor is based.

What is one kilowatt hour?

Why is tungsten used to make solenoid type coil in an electric bulb?

If in the circuit, the resistor is replaced by a motor, in which form will the energy given by the cell get transformed into?

How does the short circuit form? What is its effect?

A potential difference of 100 V is applied across a resistor of resistance 50 Ω for 6 minutes and 58 seconds. Find the heat produced in (i) joule (ii) calorie.

A potential difference of 250 volts is applied across a resistance of 1000 Ω in an electric iron. Find (1) the current (2) the heat produced in joule in 12 seconds.
Keeping other conditions the same, if the length of the wire in the iron is reduced to half the original length (by cutting the wire), what will be the current and heat produced?

Calculate the heat produced in calorie when a current of 0.1 A is passed through a wire of resistance 41.8 Ω for 10 minutes.

Find the heat produced in joule if a current of 0.1 A is passed through a coil of resistance 50 Ω for two minutes. Keeping other conditions the same if the length of the wire is reduced to the original length (by cutting 4 the wire), what will be the heat produced?

A washing machine rated 300 W operates one hour/day. If the cost of a unit is ₹ 3.00, find the cost of the energy to operate the washing machine for the month of March.

What is electromagnetic induction? Who discovered it?

Take two coils of about 50 turns. Insert them over a nonconducting cylindrical roll as shown in Figure.

(A thick paper roll can be used.) Connect coil 1 to a battery with a plug key K. Connect coil 2 to a galvanometer G. (1) Plug the key and observe the deflection in the galvanometer. (2) Unplug the key and again observe the deflection.
Note your observations. What conclusions do you draw from these observations?

Take a coil AB having 10-15 turns. Connect the two ends of the coil to the galvanometer as shown in Figure. Take a strong bar magnet. (1) Move the north pole of the magnet towards the end B of the coil.

Observe the deflection of the pointer in the galvanometer. Note the direction of the deflection (i.e. right or left). (2) Now repeat this with the south pole of the magnet towards the end B of the coil. Again observe the deflection. Note its direction. (3) What will happen if instead of the magnet, the coil is moved? (4) If both the coil and the magnet are kept stationary, do you observe any deflection? (5) Compare the direction of the deflection when the north pole of the magnet is moved towards the end B of the coil with that when the end B of the coil is moved away from the north pole of the magnet. (6) What conclusions do you draw from the observations?

Observe the following diagram and answer the questions. (Practice Activity Sheet – 1)
(a) Construction of which equipment does the following diagram show?
(b) On which principle does this equipment work?
(c) According to which law does the coil ABCD rotate?
(d) Write the law in your own words.
(e) Where is this equipment used?

Explain the application of heating effect of electric current in an electric iron.

Faraday found that electricity could produce rotational motion.

Electromagnetic induction was discovered by Coulomb.

Split rings are used in a DC generator and in an electric motor.

Electric generator converts mechanical energy into electric energy.

The electricity meter in the domestic electric circuit measures electrical energy consumption in kilowatt·hours.

A device that converts mechanical energy into electric energy.

A device that converts electric energy into mechanical energy.

The scientist in whose honour the SI unit of power is named.

A unit for intensity of magnetic field.

The unit same as the watt·second.

True or False : When more electrical appliances work together in a circuit, a short circuit result.

True or False : When live wire and neutral wire comes in contact with each other, it may cause short circuit.

True or False : The SI unit of electric current is Volt (V).

True or False : The SI unit of electric charge is coulomb (C).

True or False : The production of heat in a wire when connected to electric circuit is called heating effect of an electric current.

The unit of electric resistance is ………… .

When live wire and neutral wire come in contact, ………… takes place.

The ………… is used in the electric circuit to protect it from the loss due to excessive current.

When the potential difference between two terminals becomes ………… the electric current stops flowing.

The electric current that reverses its direction periodically with time is called ………… .

Electric bell, Electric fuse, Solenoid, Microphone

Electric oven, Electric bulb, Electric press, Electric fan

Electric heater, Electric bulb, Electric fuse, Electric press

Fuse wire, Neutral wire, Earthing wire, Live wire

Refrigerator, Electric fan, Mixer, Electric water heater