English Medium कक्षा १० - CBSE Question Bank Solutions for Science

A wire of resistance R₁ is cut into five equal pieces. These five pieces of wire are then connected in parallel. If the resultant resistance of this combination be R₂, then the ratio `R_1/R_2` is: 

(a) `1/25`

(b)1/5

(c)5

(c)25

Show with the help of diagrams, how you would connect three resistors each of resistance 6 Ω, so that the combination has resistance of (i) 9 Ω (ii) 4 Ω.

A resistor of 8 ohms is connected in parallel with another resistor X. The resultant resistance of the combination is 4.8 ohms. What is the value of the resistor X?

You are given three resistances of 1, 2 and 3 ohms. Shows by diagrams, how with the help of these resistances you can get:

(i) 6 Ω
(ii) `6/1` Ω
(iii) 1.5 Ω

How will you connect three resistors of 2 Ω, 3 Ω and 5 Ω respectively so as to obtain a resultant of 2.5 Ω? Draw the diagram to show the arrangement.

How will you connect three resistors of resistances 2 Ω, 3 Ω, and 6 Ω to obtain a total resistance of  4 Ω, and  1 Ω?

Are the lights in your house wired in series?

If current flows through two lamps arranged: 

(a) in series,
(b) in parallel,
and the filament of one lamps breaks, what happens to the other lamp? Explain your answer.

Two exactly similar electric lamps are arranged (i) in parallel, and (ii) in series. If the parallel and series combination of lamps are connected to 220 V supply line one by one, what will be the ratio of electric power consumed by them?  

Solve the following question:
In an electric circuit, two resistors of 12 0 each are joined in parallel to a 6 V battery. Find the current drawn from the battery.

The deflection of light by minute particles and molecules of the atmosphere in all directions is called ____________ of light.

One cannot see through the fog, because ____________.

Two devices are connected between two points say A and B in parallel. The physical quantity that will remain the same between the two points is:

The least resistance obtained by using 2 Ω, 4 Ω, 1 Ω and 100 Ω is:

Calculate the current flows through the 10 Ω resistor in the following circuit.

A coil in the heater consumes power P on passing current. If it is cut into halves and joined in parallel, it will consume power:

Three resistors of 1 Ω, 2 Ω and 3 Ω are connected in parallel. The combined resistance of the three resistors should be:

Assertion: When a battery is short circuited, the terminal voltage is zero.

Reason: In a short circuit, the current is zero.

You are given four ammeters A, B, C and D having the least counts mentioned below:

(I) Ammeter A with least count 0.25 A

(II) Ammeter B with least count 0.5 A

(III) Ammeter C with least count 0.05 A

(IV) Ammeter D with least count 0.1 A

Which of the ammeters would you prefer for doing an experiment to determine the equivalent resistance of two resistances most accurately, when connected in parallel?