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(a) Frequency = 500MHz = 500 x 10⁶Hz

Wavelength = 60 cm = 0.6 m

Velocity of wave = frequency x wavelength

= 500x 10⁶ x 0.6 = 3 x 10⁸m/s

(b) Electromagnetic wave is travelling through air.

Infrared radiation

Hint: Infrared radiations produce strong heating effect.

Carbon arc-lamp

(Gamma rays).

The electromagnetic radiations of wavelength from 100Å to 4000Å are called the ultraviolet radiations.

Detection: If the different radiations from the red part of the spectrum to the violet end and beyond it, are made incident on the silver-chloride solution, it is observed that from the red to the violet end, the solution remains unaffected. However just beyond the violet end, it first turns violet and finally it becomes dark brown. Thus there exist certain radiations beyond the violet end of the spectrum, which are chemically more active than visible light, called ultraviolet radiations.

Use: Ultraviolet radiations are used for sterilizing purposes.

Infrared radiations are the electromagnetic waves of wavelength in the range of 8000Å to 107Å.

Detection: If a thermometer with a blackened bulb is moved from the violet end towards the red end, it is observed that there is a slow rise in temperature, but when it is moved beyond the red region, a rapid rise in temperature is noticed. It means that the portion of spectrum beyond the red end has certain radiations which produce a strong heating effect, but they are not visible. These radiations are called the infrared radiations.

Use: The infrared radiations are used for therapeutic purposes by doctors.

(i) Infrared radiations are used in photography in fog because they are not much scattered by the atmosphere, so they can penetrate appreciably through it.

(ii) Infrared radiations are used as signals during the war as they are not visible and they are not absorbed much in the medium.

(iii) Infrared lamps are used in dark rooms for developing photographs since they do not affect the photographic film chemically, but they provide some visibility.

(iv) Infrared spectrum can be obtained only with the help of a rock-salt prism since the rock-salt prism does not absorb infrared radiations whereas a glass prism absorbs them.

(v) A quartz prism is used to obtain the spectrum of the ultraviolet radiations as they are not absorbed by quartz, whereas ordinary glass absorbs the ultraviolet light.

(vi) Ultraviolet bulbs have a quartz envelope instead of glass as they are not absorbed by quartz, whereas ordinary glad absorbs the ultraviolet light.

(a) Infrared radiations travel in straight line as light does, with a speed equal to 3 x 10⁸m/s in vacuum.

(b) They obey the laws of reflection and refraction.

(c) They do not cause fluorescence on zinc sulphide screen.

The deviation produced by the prism depends on the following four factors:

(a) The angle of incidence - As the angle of incidence increases, first the angle of deviation decreases and reaches to a minimum value for a certain angle of incidence. By further increasing the angle of incidence, the angle of deviation is found to increase.

(b) The material of prism (i.e., on refractive index) - For a given angle of incidence, the prism with a higher refractive index produces a greater deviation than the prism which has a lower refractive index.

(c) Angle of prism- Angle of deviation increases with the increase in the angle of prism.

(d) The colour or wavelength of light used- Angle of deviation increases with the decrease in wavelength of light.

(a) Ultraviolet radiations produce fluorescence on striking a zinc sulphide screen.

(b) They cause health hazards like cancer on the body.

(b)  2E.

Explanation:- 

Since (k_A = 2k_B) it means for the same force x_B = 2x_A . So if energy stored in spring A = E = F.x_A   Energy stored in spring B = F.x_B =F.2x_A =2E 

(b)  2E.

Explanation:- 

Since (k_A = 2k_B) it means for the same force x_B = 2x_A . So if energy stored in spring A = E = F.x_A   Energy stored in spring B = F.x_B =F.2x_A =2E 

The deviation caused by a prism increases with the decrease in the wavelength of light incident on it.

(i)Ultraviolet rays-wavelength range 100 Å to 4000 Å

(ii)Visible light-wavelength range 4000 Å to 8000 Å

(iii)Infrared radiations-wavelength range 8000 Å to 107 Å

Green, Yellow orange and red have wavelength longer than blue light.

Data : Width, L = 250 m, depth H = 40 m, ρ = 1000 kg/m³ , g = 9.8 m/s²

Since pressure increases linearly with depth, the average pressure p_av due to the weight of the water is the pressure at the average depth h of 20 m. The force exerted on the dam by the water is the average pressure times the area of contact, F = p_av A = p_av LH.

(i) p_av = hρg = (20)(1000)(9.8) = 1.96 × 10⁵Pa

(ii) F = p_avA = p_avLH = (1.96 × 10⁵)(250)(40) = 1.96 × 10⁵N

Both deviation and dispersion.

Hint: When a white light ray falls on the first surface of a prism, light rays of different colours due to their different speeds in glass get refracted (or deviated) through different angles. Thus, the dispersion of white light into its constituent colours takes place at the first surface of prism.

The colour of the extreme end opposite to the base of the prism is red.

Hint: The angle of deviation decreases with the increase in wavelength of light for a given angle of incidence. Since the red light has greatest wavelength, it gets deviated the least and is seen on the extreme end opposite to the base of prism.

(a) Violet, Indigo, Blue, Green, Yellow, Orange, Red.

(b) No, different colours have different widths in the spectrum.

(c) (i) Violet colour is deviated the most. (ii) Red colour is deviated the least.

As the light travels through the atmosphere, it gets scattered in different directions by the air molecules present in its path. The blue light due to its short wavelength is scattered more as compared to the red light of long wavelength. Thus the light reaching our eye directly from sun is rich in red colour, while the light reaching our eye from all other directions is the scattered blue light. Therefore, the sky in direction other than in the direction of sun is seen blue.

Scattering property of light is responsible for the blue colour of the sky as the blue colour is scattered the most due to its short wavelength.

Speed of light increases with increase in the wavelength.

Red colour travels fastest and Blue colour travels slowest in glass.

1. vapor on cooling water

2. water on cooling Ice

1. Ice cube on heating water.

2. Water on heating vapor.

When an object is immersed in water, it exerts a downward force on water and the water, in turn, exerts an upward force or upthrust on the objects. The upthrust is equal to the mass of the liquid displaced. It is this upthrust that keeps a body afloat. This upthrust is called the force of buoyancy.

The other classifications of matter are

1. Elements

2. Compounds and

3. Mixtures.

The density depends on two factors:

1. Mass of each particle.

2. Compactness of arrangement of these particles.

Correct answer is c. Pressure

The three forms of matter are solids, liquids, and gases.

1. Volume is the amount of space occupied by matter.

2. Plasma is the fourth state of matter.

3. Visible matter is made up of invisible particles.

1. Mass is the quantity of matter in a given object (or) a substance.

2. Pressure is the force exerted on a unit area.

1. The law of conservation of matter is given bv the scientist John Dalton.

2. The elements are classified into metals and nonmetals.

b. Definite shape and definite volume.

Correct answer is d. Gases

The movement of solvent molecules through a semipermeable membrane in a solution from a low high concentration till the concentration on both sides becomes equal is called ‘Osmosis’.

D) a, b, d, c, e

C) Both plants and animals

Correct option is A) Osmosis

Saturated solution: It is a solution in which solute further can not dissolve.

True 

Vacuole is a single membrane organelle that is used for storage of water and other nutrient molecules.

D. Locomotion

Vacuoles are single membrane bound cell organelles that are involved in storage, maintaining cell structure and waste excretion. It does not aid the cell in locomotion.

Correct option is B) Liquids

Correct option is D) All

C. Lysosome

Lysosomes comprise around fifty different degradative catalysts that can hydrolyze proteins, DNA, RNA, polysaccharides, and lipids. Changes in the qualities that encode these catalysts are answerable for in excess of 30 distinctive human hereditary illnesses, which are called lysosomal capacity sicknesses on the grounds that undegraded material collects inside the lysosomes of influenced people. A large portion of these illnesses result from lack in single lysosomal catalysts. For instance, Gaucher's illness (the most widely recognized of these issues) results from a change in the quality that encodes a lysosomal compound needed for the breakdown of glycolipids. A charming special case is I-cell illness, which is brought about by an inadequacy in the compound that catalyzes the initial phase in the labeling of lysosomal proteins with mannose-6-phosphate in the Golgi contraption. The outcome is an overall disappointment of lysosomal proteins to be fused into lysosomes.

Correct option is C) Swellup

B) Endocytosis

Common cold, Malaria and chicken pox can be transmitted from individual to individual. Anaemia is not transmitted as such and is mainly caused by blood loss.

The role of placenta is to provide all the developing requirements to the developing foetus.

These requirements are:

• Nutrition

• Respiration

• Excretion etc