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A person walks with velocity V in a straight line forming an angle theta with the plane of a plane mirror. Find the velocity V relative with which he approaches his image

If V be the velocity of approach at an angle θ, then velocity along the perpendicular direction will be Vsinθ.... View Article

In the game of cricket, the stump falls down when a ball strikes it this the example of which force? a] frictional force b] gravitational force c]muscular force c] none of these

The contact forces represent the result of physical contact between two objects, one by which force is exerted and the... View Article

Citrus fruits are acidic in nature, then why are they grown in alkaline soil? Even if there is a neutralization reaction, the product or fruits should be neutral. Why isn’t it so?

According to dietitian Benjamin White, despite their acidic nature citrus fruits are actual an alkalizing agent on the body. “Citrus... View Article

An object is placed at a distance of 10cm from a diverging mirror of focal length 15 cm . Find the position and of the image formed also calculate the magnification of the image .

Answer: The given parameters u = -10 cm f = 15 cm We know the formula 1/f = 1/v +... View Article

Simple interest on a certain sum of mine at 9% is rupees 450 in 2 years. Find the compound interest on the same sum at the same rate for 1 year if the interest is reckoned half-yearly

Simple interest for 1 year = 450/2 =225 let x be the principal 9x/100=225 x=2500 2500*(9/100)= 225 capital for the... View Article

Do pulmonary arteries give blood to oxygen for oxygenation of the blood and pulmonary veins take in the oxygen rich blood and give it to the aorta to supply the blood in the whole body?

Heart continuously pumps oxygen and nutrient-rich blood throughout your body to sustain life. Blood is essential. In addition to carrying... View Article

When an object is placed in front of a concave mirror at a distance 30cm from an image is obtained on a screen at a distance of 20cm from the mirror. Find the focal length of the mirror.

Here given that, u= -30 cm f= -20 cm By using mirror formula, 1/v + 1/u = 1/f 1/v +... View Article

Stars have a brighter light than Sun. Hence they are not visible in the morning but then why is the moon visible for like at least till 10 am in the morning. Give reasons to support your answer

The moon is only in this position for a single instant in the whole lunar month: the exact time of... View Article

The distance between Delhi and Agra is 200km a train travels the first 100km at speed of 50km/h how fast must the train travel next 100km so that the average speed is 70km/h for the whole journey

Time taken to travel first half distance = 100/ 50 = 2 hrs Time is taken to travel second half... View Article

A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R′, then the ratio R/R′ is: (a) 1/25 (b) 1/5 (c) 5 (d) 25

Resistance is proportional to the length of wire and inversely proportional to the area of cross-section. IF length is 1/5th,... View Article

A boy is sitting in a merry-go-round which is moving with a constant speed of 10 m/s. This means that the boy is (A) at rest (B) moving with no acceleration (C) in accelerated motion (D) moving with uniform velocity.

Answer: (C) in accelerated motion The boy is moving constantly at a speed of 10 m/s and since the direction is... View Article

A composite resistance of 50 ohm which can carry a current of 4A is to be made from resistances each of resistance 100ohm which can carry a current of 1A. the minimum number of resistances to be used is: a) 4 b) 8 c) 12 d) 16.

Given that, Composite resistance = 50 ohm Current = 4 A Each resistance = 100 ohm Each resistance carry a... View Article

When scattering of light takes place in a colloidal solution the particles in it scatters light but did light passes through the particle which scatters it and moves to next particle or does the particle of colloid absorbs light?

The Tyndall effect is light scattering by particles in a colloid or in a very fine suspension. When light is... View Article

A and B are partners sharing profit and losses in the ratio 3:2. They decided to admit C as a partner for 1/4th share. New ratio and sacrificing ratio will be There is a option for above mentioned question (a) 9:7:6 , 3:2 (b) 3:2:1, 3:2 (c) 10:5:5 , 3:5

Old ratio (A and B) = 3 : 2 C is admitted for 1/4 share Let the combined share of... View Article

Explain what happens to the molecular motion and energy of 1kg of water at 273K when it changes to the ice at the same temperature. How it is the latent heat of fusion related to the energy exchange that takes place during this change of state?

When water is converted to the ice at the same temperature, there are changes involved in internal potential energy. The... View Article

A restaurant hall is 20 metres long, 15 metres wide and 10 metres high. The interior of the hall except the ceiling and the base has to be covered with a bright wall paper. What will be the total expenditure if the wall paper costs Rs.60 per square metre?

Length = 20 m Breadth = 15 m Height = 10 m To find: Total costing to cover the walls... View Article

The teacher instructed three students ‘A’, ‘B’ and ‘C’ respectively to prepare a 50% (mass by volume) solution of sodium hydroxide (NaOH). ‘A’ dissolved 50g of NaOH in 100 mL of water, ‘B’ dissolved 50g of NaOH in 100g of water while ‘C’ dissolved 50g of NaOH in water to make mL of solution. Which one of them has made the desired solution?

Answer: C has made the desired solution Student A and B prepare 150 ml solution, so student C make desire... View Article

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