PART - 3 CH - 11 Electricity Science - PART - 3 CH - 11 Electricity

Which of the following physical quantities has unit kWh ?

Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combinations would be -

An electric bulb is rated 220 V and 100 W . When it is operated on 110 V , the power consumed will be __________.

The SI unit of electric potential difference is named after the Scientist _______.
(Andre - Marie Ampere, Alessandro Volta, Georg Simon Ohm)

The rate of consumption of electric energy with time is called __________ (Electric current, Electric power, Electric charge)

The following symbol indicates a battery : 

Work can be expressed in coulomb-volt.

Electric charge is measured by using an ammeter.

For two wires of the same material and having the same length, the resistance of the thicker wire is less than that of the other wire.

What is meant by saying that the potential difference between two points is 1 V ?

Name a device that helps to maintain a potential difference across a conductor.

How much work is done in moving a charge of 2C across two points having a potential difference 12 V ?

I measure the electric current. Which device am I?

Define : Electric current.

A current of 0.5 A is drawn by a Filament of an electric bulb for 20 minutes. Find the amount of electric charge that I lows through the circuit

When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.

The potential difference between the terminals of an electric heater is 60 V When it draws a current of 4 A from the Source. What current will the heater draw if the potential difference is increased to 120 V ?

Vishva noticed in a dhaba around 50 bulbs, each of 100 W all were glowing. She calculated the cost of electricity consumed in one hour and told the dhaba owner to reduce the expenses and at the same time save electricity by using CFL bulbs instead of ordinary filament-type bulbs.
(1) What would be the cost of electric energy if 50 bulbs, each of 100 W , are used for one hour? 1 unit costs ₹ 5 .
(2) What is a CFL?
(3) What value did Vishva display in the above case?

Mitali's mother was cooking in the kitchen for guests. Mitali saw her mother had plugged in microwave, hot plate and food processor on the same plug point. She immediately switched off the plug and removed all the plugs and re-plugged them in separate individual plugs.
(1) What happens when we use too many electrical devices plugged in one power point?
(2) What is the power of a device?
(3) What value did Mitali display in the above act?

Bharat was doing an experiment by using an ammeter. Suddenly, it fell from his hand and broke. He was afraid, that he might be scolded and threaten by his teacher. His classmate advised him not to tell the teacher, but he refused and told his teacher. On listening to him patiently, the teacher did not scold him and threaten as it was just an accident and used the opportunity to show the internal structure of the ammeter to the whole class.
On the basis of above passage, answer the following questions :
(1) What values do you learn from Bharat?
(2) What is the use of ammeter? How is it connected in the circuit?
(3) State the aim of any one experiment, where Bharat could have used the ammeter.

(1) What is a circuit diagram?
(2) Draw a labelled diagram of an electric circuit comprising a battery, electric bulb, ammeter and plug key (closed). Show the direction of the conventional current.
(3) Symbols of some components are given below. Using all of them only once draw an appropriate circuit diagram. Assume you are already having the wires for connection.

Also name each component used.

Explain the series combination of resistors and derive the formula of equivalent resistance.

Give reasons why different electrical appliances in a domestic circuit are connected in parallel.###Which type of connection is seen in a domestic circuit? Describe its uses or advantages.

Two lamps, one rated 100 W at 220 V , and the other 60 W at 220 V are connected in parallel to electric mains supply. What current is drawn from the line if the supply voltage is 220 V ?

Column I	Column II	Column III
Q.1. Resistance	a. VIt	p. The joule
Q.2. Electric energy	b. Q/t	q. The volt / ampere
	c. V/I	r. The coulomb / second

 

Column I	Column II	Column III
Q.1. Copper	a. Resistor	p. It is used to make resistance.
Q.2. Nichrome	b. Semi- conductor	q. It is used to make conduc - ting wire.
	c. Conductor	r. It is used to make elec - tronic   components.

 

Column I	Column II	Column III
Q.1. Wood	a. Resistor	p. It is used to make resistance.
Q.2. Silicon	b. Semi- conductor	q. It stops electric current.
	c. Insulator	r. It is used to make elec - tronic   components.