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keep on increasing

Explanation:

• If we take the entire room including the air and the refrigerator as the system, which is an adiabatic closed system since the heat transfer from the room is negligible.
• The only energy interaction involved is the electric energy crossing the system boundary and entering the room.
• The conservation of energy required the energy content of the room to increase by an amount equal to the amount of energy drawn by the refrigerator.
• The refrigerator or its motor does not store this energy.
• Therefore this energy must now be in room air and it will manifest itself as a rise in the air temperature.

Stoke’s law:

When a body falls through a highly viscous liquid, it drags the layer of the liquid immediately in contact with it. This results in a relative motion between the different layers of the liquid. As a result of this, the falling body experiences a viscous force F.

Stoke performed many experiments on the motion of small spherical bodies in different fluids and concluded that the viscous force F acting on the spherical body depends on

1. Coefficient of viscosity q of the liquid 

2. Radius a of the sphere and 

3. Velocity v of the spherical body

Dimensionally it can be proved that 

∴ F = k ηav 

Experimentally Stoke found that k = 6π 

This is Stoke’s law 

Terminal velocity: 

Terminal velocity of a body is defined as the constant velocity acquired by a body while falling through a viscous liquid.

Geostationary Satellite: It is the satellite which appears at a fixed position and at a definite height to an observer on Earth. 

Polar Satellite: It is the satellite which revolves in polar orbit around the Earth.

(i) People who live in glass houses should not throw stones. 

(ii) You ought to wipe your feet before coming into the house, especially during the rains. 

(iii) You should do what the teacher tells you. 

(iv) The pupils were told that they should write more neatly. 

(v) Sign in front of a park: You must not walk on the grass. 

(vi) You should be ashamed of yourself having made such a remark. 

(vii) He left home at 9 o’clock. He should be here any minute. 

(viii) “Whatever happened to the chocolate cake?” “How should I know? I have just arrived.”

The sentences in the text which express the author’s disapproval of his friend shaking the bicycle violently are as follows: 

(i) I said, “Don’t do that; you’ll hurt it.” 

(ii) I did not see why he should shake it; it had not done anything to him. 

(iii) Besides, if it wanted shaking, I was the proper person to shake it. I felt much as I should had he started whacking my dog.

When the author returned from the tool shed, he saw his friend sitting on the ground with the front wheel between his legs. He was playing with it, twiddling it round between his fingers, and the remnant of the machine was lying on the gravel path beside him

The author’s friend tightened the chain till it did not move. Then he loosened it until it was twice as loose as it was before.

The author’s friend wanted to check the chain of the bicycle. For this, he began taking off the gear­case. The author tried to dissuade him from doing that by telling him that if anything does go wrong with the gear­case of a bicycle, then it is cheaper to sell the bicycle than set about repairing the damaged gear­case. However, his friend disagreed and said that nothing was easier than taking off a gear­case. The author notes with sarcasm that his friend was indeed right. In less than five minutes, he had the gear­case in two pieces, lying on the path. 

 a) longitudinal strain b) shearing strain c) bulk strain

Within elastic limit stress and strain are proportional to each other. Stress ∝ strain OR stress/stain = constant (modulus of elasticity). 

a) longitudinal stress b) shearing stress 

(d) may be represented in terms of L, T and x if a ≠0.

Explanation:

a≠0 If a = 0, then we cannot represent mass dimensionally in terms of L, T and x, otherwise it can be represented in terms of L, T and x.

B. half life

A. random process

Correct Answer is: (c) Statement-1 is True, Statement-2 is False.

Correct Answer is: (d) four times the energy finally stored in the capacitor

The charge on the capacitor will change from -ℰC to +ℰC,

where ℰ = emf of each cell.

∴ total charge flowing through the cell B is 2ℰC.

∴ total energy supplied by B is 2ℰ²C.

The energy finally stored in the capacitor is ℰ = 1/2 ℰ²C.

∴ heat produced = 2ℰ²C = 4ℰ.

Correct option (a) 2 

Explanation:

Total no. of cells, = mn = 100

Current will be maximum when R = nr/m; 25 = n x 1/m

⇒ n = 25 m 

From equation (i) and (ii)

n = 50 and m = 2

Since it is a closed system. 

Δu = q – w 

Δu = 10J – 15J Δu = -5J

Metal Plating Process:

• Metal plating is a finishing process in which a thin coating of metal is deposited on another object.
• Metal plating Services provide many advantages to products manufactured from metal and other materials.
• By Metal plating an object with a refined metal, we can achieve desired properties such as providing corrosion and heat protection, increasing solderability, and improving the strength and hardness.
•  Metal plating can also be used for aesthetics on items such as furniture.
• This allows your items to maintain their luster long-lasting.
• Metal plating and metal plating services have been around for hundreds of years.
• This process is vital for advanced technology. There are several metal plating methods and many variations.
• Silver has the highest electrical conductivity in comparison to all metals.
• The crystal structure of silver is a face-centered cubic lattice with a single valence electron, that allows for efficient heat and thermal conductivity.
• Silver is in fact the standard for electrical conductivity. All other metals are assessed in reference to it.
• Silver is the benchmark of 100 on the electrical conductivity scale.
• It however does not possess much wear resistance.
• But due to its excellent optical reflectivity, it is used commonly to coat mirrors and plating conductors in electronics and communication devices that do not generate much heat.

Correct answer is (a) decreases

(a) its wavelength decreases

Wavelength, λ = \(\frac{velocity}{frequency}\) = \(\frac{u}{v}\)

When light travels from air to glass, frequency ν remains unchanged, velocity u decreases and hence wave length λ also decreses

(c) 12 cm 

Let d₁ = 5 cm and d₂ = 3 cm ; n = 1.5 

Actual width is the sum of real depth from 2 sides 

Thickness of slab = d₁ n + d₂ n 

= (5 x 1.5) +(3 x 1.5)= 12 cm

Correct Answer is: (d) Statement-1 is False, Statement-2 is True.

(A) (vector τ = M x B)