English Medium Class 10 - CBSE Question Bank Solutions for Science

Which of the following statement is correct?

Draw ray diagram showing myopic eye.

A student sitting at the back of the classroom cannot read clearly the letters written on the blackboard. What advice will a doctor give to her? Draw ray diagram for the correction of this defect.

A person needs a lens of power –4.5 D for correction of her vision.

1. What kind of defect in vision is she suffering from?
2. What is the focal length of the corrective lens?
3. What is the nature of the corrective lens?

When do we consider a person to be myopic or hypermetropic? Explain using diagrams how the defects associated with myopic and hypermetropic eye can be corrected?

A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistances R₁, R₂ and R₃ respectively. Which of the following is true? 

Calculate the total resistance of the circuit and find the total current in the circuit.

These consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:

Assertion: Silver bromide decomposition is used in black and white photography.

Reason: Light provides energy for this exothermic reaction.

1. Identify the gasses evolved at the anode and cathode in the above experimental set up.
2. Name the process that occurs. Why is it called so?
3. Illustrate the reaction of the process with the help of a chemical equation.

State Ohm's Law. Represent it mathematically.

What is the resistance of a conductor through which a current of 0.5 A flows when a potential difference of 2V is applied across its ends?

You are provided with a resistor, a key, an ammeter, a voltmeter, four cells of 1.5 V each and few connecting wires. Using circuit components, draw a labelled circuit diagram to show the setup to study Ohm's law.

State the relationship between potential difference (V) across the resistor and the current (I) flowing through it. Also draw V-I graph, taking V on the X-axis.

Let the resistance of an electrical device remain constant, while the potential difference across its two ends decreases to one fourth of its initial value. What change will occur in the current through it? State the law which helps us in solving the above stated question. 

State reasons for Myopia. With the help of ray diagrams, show the:

1. image formation by a myopic eye, and
2. correction of myopia using an appropriate lens.

What is meant by resistance of a conductor ? Define its SI unit.

A metal nitrate 'A' on heating gives a metal oxide along with evolution of a brown coloured gas 'B' and a colourless gas, which helps in burning. Aqueous solution of 'A' when reacted with potassium iodide forms a yellow precipitate.

1. Identify 'A' and 'B'
2. Name the types of the reactions involved in the above statement.

A person is unable to see clearly a poster fixed on a distant wall. He however sees it clearly when standing at a distance of about 2 m from the wall.

1. Draw ray diagram to show the formation of image by his eye lens when he is far away from the wall.
2. List two possible reasons of this defect of vision.
3. Draw ray diagram to show the correction of this defect using appropriate lens.

The resistance of a resistor is reduced to half of its initial value. If other parameters of the electrical circuit remain unaltered, the amount of heat produced in the resistor will become ______.

Observe the following diagram and answer questions following it: 

1. Identify the defect of vision shown.
2. List its two causes.
3. Name the type of lens used for the correction of this defect.