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Define the following terms : (i) Power of a lens (ii) Principal focus of a concave mirror

(i) Power of a lens It is the Ability of a lens to converge or diverge light rays/reciprocal of focal... View Article

An object is placed perpendicular to the principal axis of a convex mirror of focal length 10 cm. The distance of the object from the pole of the mirror is 10 cm. Find the position of the image formed.

Focal length, f = 10cm Object distance, u = −10cm (object distance is always taken negative as it is on the left side) To find: Position... View Article

A concave mirror of focal length 10 cm can produce a magnified real as well as virtual image of an object placed in front of it. Draw ray diagrams to justify this statement.

(a) A concave mirror of focal length 10 cm can produce a magnified real image when the object is placed... View Article

A current of 500 mA flows in a series circuit containing an electric lamp and a conductor of 10 Ω when connected to 6 V battery. Find the resistance of the electric lamp.

Current, I = 500 mA = 0.5 A (converted milliampere to ampere)... View Article

Find the ratio of resistances of two copper rods X and Y of lengths 30 cm and 10 cm respectively and having radii 2 cm and 1 cm respectively.

We have to find ratio of resistance of two copper rods Length of wire X = 30 cm Length of wire Y = 10 cm Radius... View Article

Mention the changes which the uterus undergoes, when (i) it has to receive a zygote. (ii) no fertilization takes place.

(i) The uterus prepares itself every month to receive a fertilized egg/zygote- The inner uterus lining (endometrium) becomes thick and... View Article

In the female reproductive system of human beings, state the funtions of (i) ovary (ii) oviduct

In the female reproductive system, the function of (i) ovary is to produce one egg every month. It is also... View Article

Unsafe sexual act can lead to various infections. Name two bacterial and two viral infections caused due to unsafe sex.

Unsafe sexual acts can lead to sexually transmitted diseases. The two examples of sexually transmitted diseases caused by (i) virus:... View Article

Why has Government of India prohibited prenatal sex determination by law? State its benefits in the long run.

Government of India has prohibited prenatal sex determination by law to reduce the indiscrimination of female foeticide. Because of which... View Article

List two factors on which reabsorption of water from urine depends?

Reabsorption of water from the urine depends upon the amount of water present in the body and the level of... View Article

Define the following terms giving one example of each. (i) Esterification (ii) Addition reaction

Esterification The reaction of carboxylic acid with an alcohol in the presence of H2SO4 yields an ester.When primary alcohol is... View Article

What happens when (Write the balanced equation involved) – (i) Copper is heated in air? (ii) Aluminium oxide is reacted with hydrochloric acid? (iii) Potassium reacts with water? (iv) Cinnabar is heated in air? (v) Aluminium oxide reacts with sodium hydroxide?

(i) Copper is heated in air to form the black copper oxide. The equation for the reaction is given below: 2Cu +... View Article

Draw a labelled diagram of electrolytic refining of copper.

Reaction for electrolytic refining: The impure copper metal is made ANODE and the pure metal of copper is CATHODE copper... View Article

How is the method of extraction of metals high up in the reactivity series different from that for metals in the middle? Why cannot the same process be applied for them? Name and explain the process of extraction of sodium.

Metals high up in reactivity series are extracted by electrolytic reduction. While those in the middle are extracted first by... View Article

Complete the path of white light when it passes through two identical prisms placed as shown :

The cause of dispersion is the change in speed of light with wavelength .when white light enters the first surface... View Article

The apparent position of an object, when seen through the hot air, fluctuates or wavers. State the basic cause of this observation.

The apparent position of an object, when seen through the hot air, fluctuates or wavers. The basic cause of this... View Article

Two coils of insulated copper wire are wound over a non-conducting cylinder as shown. Coil 1 has comparative large number of turns. State your observations, when (i) Key K is closed. (ii) Key K is opened. Give reason for each of your observations

(i) A momentary deflection is shown by the galvanometer. (ii) A momentary deflection is shown by the galvanometer but in... View Article

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