English Medium Class 10 - CBSE Important Questions

When light enters the atmosphere it strikes extremely fine particles, which deflect the rays of light in all possible directions, This is due to ______.

When a beam of white light passes through a region having very fine dust particles, the colour of light mainly scattered in that region is ______.

Name the phenomenon of light responsible for Tyndall effect. Write an event where this phenomenon can be observed.

What does an electric circuit mean?

A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R’, then the ratio `"R"/"R'"` is ______.

Which of the following terms does not represent electrical power in a circuit?

What is meant by "electric power"?

Draw a schematic diagram of an electric circuit consisting of a battery of two cells each of 1.5 V, 5 Ω, 10 Ω and 15 Ω resistors and a plug key, all connected in series.

Distinguish between an open and a closed circuit.

Calculate the resistance of an electric bulb which allows a 10 A current when connected to a 220 V power source.

State the relation between work, charge and potential difference for an electric circuit.

Define 1 kilowatt hour. 

Write the relation between resistance and electrical resistivity of the material of a conductor in the shape of a cylinder of length `'l'`  and area of cross-section `'A'` . Hence derive the S.I. unit of electrical resistivity.

Resistance of a metal wire of length 5 m is 100 Ω . If the area of cross - section of the wire is `3 × 10^-7  "m"^2` , Calculate the resistivity of the metal . 

Consider the sacle of voltmeter shown in the diagram and answer the following questions : 

(a) What is the least count of the voltmeter?

(b) What is the reading shown by the voltmeter ?

(c) If the voltmeter is connected across a resistor of 20 `Omega` how much current is flowing through the resistor?

State the relation correlating the electric current flowing in a conductor and the voltage applied across it. Also, draw a graph to show this relationship.

Answer the following question.
What is the function of a galvanometer in a circuit?

Define electric power. An electrical device of resistance R is connected across a source of voltage V and draws a current I. Derive an expression for power in terms of current and resistance.

Two electric bulbs rated 100 W; 220 V and 60 W; 220 V are connected in parallel to electric mains of 220 V. Find the current drawn by the bulbs from the mains.