Selina solutions for Concise Physics [English] Class 9 ICSE chapter 9 - Current Electricity [Latest edition]

Name one D.C. source and one A.C. source. 

Distinguish between D.C. and A.C.

What is an electric cell? 

What transformation of energy takes place when current is drawn from a cell? 

Name the constituents of a cell. 

n electrons flow through a cross section of a conductor in time t. If charge on an electron is e, then write an expression for the current in the conductor. 

In the electric circuit shown in Figure, label the parts A, B, C, D, E, and F. State the function of each part. Show in the diagram the direction of flow of current.

Write symbol and state function of following component in an electric circuit :

cell

Write symbol and state function of following component in an electric circuit :

rheostat

Write symbol and state function of following component in an electric circuit :

ammeter

Write symbol and state function of following component in an electric circuit :

voltmeter

(a) Complete the circuit given in Fig. by inserting between the terminals  A and C. an ammeter.

(b) In the diagram, mark the polarity at the terminals of ammeter and indicate clearly the direction of flow of current in the circuit when the circuit is complete.

(c) Name and state the purpose of Rh in the circuit.

Select conductors of electricity from the following: Copper wire, silk thread, pure water, acidulated water, human body, glass, mercury. 

Distinguish between a closed circuit and an open circuit, with the use of suitable labelled diagrams. 

A cell is used to :

The unit of current is :

The insulator of electricity is : 

A charge 0.5 C passes through a cross section of a conductor in 5 s . Find the current .

A current of 1.5 A flows through a conductor for 2.0 s . What amount of charge passes through the conductor ?  

When starter motor of a car is switched on for 0.8 s . a charge 24 C passes through the coil of the motor . Calculate the current in the coil .

Figure. below shows two conductors A and B. Their charges and potentials are given in diagram. State the direction of (i) flow of electrons and (ii) flow of current, when both the conductors are joined by a metal wire.

How is the direction of flow of current between the two charged conductors determined by their potentials? 

Explain the concept of electric potential difference in terms of work done in transferring the charge.  

State Ohm's law.

How is the current flowing in a conductor changed if the resistance of conductor is doubled keeping the potential difference across it the same? 

State three factors on which the resistance of a wire depends. Explain how the resistance depends on the factors stated by you. 

State whether the resistance of filament of a bulb will decrease, remain unchanged or increase when it glows.

Name the physical quantity of which the unit is coulomb

Name the physical quantity of which the unit is ohm 

Name the physical quantitiy of which the unit is ampere

Current in a circuit flows : 

The unit of potential difference is : 

On increasing the resistance in a circuit, the current in it : 

A cell of potential difference 12 V is connected to a bulb. The resistance of filament of bulb when it glows is 24Ω. Find the current drawn from the cell.

A bulb draws current 1.5 A at 6.0 V. Find the resistance of filament of bulb while glowing.

A current 0.2 A flows in a wire of resistance 15Ω. Find the potential difference across the ends of the wire.

What is meant by the efficient use of energy?

State two ways to save the energy.

How does the proper insulation of home save energy?

Which of the following device is most efficient for the lighting purpose?

LED, CFL, fluorescent tube light, Electric bulb.

Give an example to explain that the use of modem eco-friendly technology is more efficient and less polluting.

Describe three ways for the efficient use of energy.

What social initiatives must be taken for the sensitive use of energy?

The most non-polluting and efficient lighting device is :

IEA is the short form of :