Archives

A man is pushing a cart down a slope. Suddenly the cart starts moving faster and he wants to slow it down. What should he do?

Answer: Man can accomplish the following He can start dragging the cart instead of pushing it to resist gravity's downward force. He can travel... View Article

A marble is allowed to roll down an inclined plane from a fixed height. At the foot of the inclined plane, it moves on a horizontal surface (a) covered with silk cloth (b) covered with a layer of sand and (c) covered with a glass sheet. On which surface will the marble move the shortest distance. Give the reason for your answer.

Answer: Because it will exert a greater amount of friction on the marble, it will move the shortest distance on the layer of sand, while the... View Article

A place receives very little rainfall and the temperature is high throughout the year, the climate of that place will be _ and _ .

Answer: A place receives very little rainfall, and the temperature is high throughout the year, the climate of that place will be hot and dry.... View Article

A simple pendulum makes 10 oscillations in 20 seconds. What is the time period and frequency of its oscillation?

Answer: Given parameters Time period (t) - 2s frequency (f) - 0.5 oscillations/sec A pendulum makes 10 oscillations in 20 seconds Frequency (f)... View Article

A small hole P is made in a piece of cardboard. The hole is illuminated by a torch as shown in Fig. The pencil of light coming out of the hole falls on a mirror. At which point should the eye be placed so that the hole can be seen? (a) A (b) B (c) C (d) D

Answer: (a) A The eye should be placed at position A because the hole can be seen only when the angle of incidence is equal to the angle of... View Article

A star is ten light-years away from the earth. Suppose it brightens up suddenly today. After how much time shall we see this change?

Answer: 1 light-year= distance covered by light in one year. 10 light-years away from the earth glow today, then it will be seen after 10 years.... View Article

A tester is used to check the conduction of electricity through two liquids, labelled A and B. It is found that the bulb of the tester glows brightly for liquid A while it glows very dimly for liquid B. You would conclude that (i) liquid A is a better conductor than liquid B. (ii) liquid B is a better conductor than liquid A. (iii) both liquids are equally conducting. (iv) conducting properties of liquid cannot be compared in this manner.

Answer: (i) liquid A is a better conductor than liquid B The amount of current flowing through a solution is determined by its conductivity. The... View Article

A tiny mirror M is fixed on a piece of cardboard placed on a table. The cardboard is illuminated by light from a bulb. The position of the eye with respect to the position of the bulb is shown in Fig. as A, B, C and D. In which position mirror will be visible? a. A b. B c. C d. D

Answer: (a) A When a ray of light from the bulb strikes the mirror M, according to the laws of reflection of light, it will be reflected back... View Article

A toy car released with the same initial speed will travel farthest on (a) muddy surface (b) polished marble surface (c) cemented surface (d) brick surface

Answer: (b) polished marble surface Because a polished marble floor has the least frictional force and inertia, a car will move farthest on it.... View Article

A water tank has four taps fixed at points A, B, C, D as shown in Fig. The water will flow out at the same pressure from taps at (a) B and C (b) A and B (c) C and D (d) A and C

Answer: (a) B and C B and C are at the same level, hence pressure will be the same at B and C. Fluid pressure is the pressure at a point within... View Article

An alarm bell is kept inside a vessel as shown in Fig. A person standing close to it can distinctly hear the sound of the alarm. Now if the air inside the vessel is removed completely how will the loudness of alarm get affected for the same person?

Answer: Air needs a medium to get transmitted. If we slowly remove the air inside the bottle. Sound will not be having medium to travel as it... View Article

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Archives

A man is pushing a cart down a slope. Suddenly the cart starts moving faster and he wants to slow it down. What should he do?

A place receives very little rainfall and the temperature is high throughout the year, the climate of that place will be _ and _ .

A simple pendulum makes 10 oscillations in 20 seconds. What is the time period and frequency of its oscillation?

A small hole P is made in a piece of cardboard. The hole is illuminated by a torch as shown in Fig. The pencil of light coming out of the hole falls on a mirror. At which point should the eye be placed so that the hole can be seen? (a) A (b) B (c) C (d) D

A star is ten light-years away from the earth. Suppose it brightens up suddenly today. After how much time shall we see this change?

A tiny mirror M is fixed on a piece of cardboard placed on a table. The cardboard is illuminated by light from a bulb. The position of the eye with respect to the position of the bulb is shown in Fig. as A, B, C and D. In which position mirror will be visible? a. A b. B c. C d. D

A toy car released with the same initial speed will travel farthest on (a) muddy surface (b) polished marble surface (c) cemented surface (d) brick surface

A water tank has four taps fixed at points A, B, C, D as shown in Fig. The water will flow out at the same pressure from taps at (a) B and C (b) A and B (c) C and D (d) A and C

Add the following: 2p²q² – 3pq + 4, 5 + 7pq – 3p²q²

Add the following: a – b + ab, b – c + bc, c – a + ac

Add the following: ab – bc, bc – ca, ca – ab

Add the following: l² + m², m² + n², n² + l², 2lm + 2mn + 2nl

Add: 2x (z – x – y) and 2y (z – y – x)

Add: p ( p – q), q ( q – r) and r ( r – p)

Air moves from a region of _ pressure to a region of_ pressure.

All the stars are at the same distance from us. (True or False)

Ammonia is found in many household products, such as window cleaners. It turns red litmus blue. What is its nature?

An alarm bell is kept inside a vessel as shown in Fig. A person standing close to it can distinctly hear the sound of the alarm. Now if the air inside the vessel is removed completely how will the loudness of alarm get affected for the same person?

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