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Choose the correct option. A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each (A) two revolutions (B) One revolution (C) half revolution (D) one-fourth revolution

Answer: (C) half revolution The direction of the induced current varies once every half revolution when a rectangular coil is rotated in a... View Article

A taxi-driver, filled his car petrol tank with 40 liters of petrol on Monday. The next day, he filled the tank with 50 liters of petrol. If the petrol costs Rs. 44 per liter, how much did he spend in all on petrol?

Given that Petrol filled on Monday = 40 liters Petrol filled on next day = 50 liters Cost of 1 liter petrol = Rs. 44 Find out We have to... View Article

A spherical mirror and a thin spherical lens have each a focal length of -15 cm. The mirror and the lens are likely to be (A) both concave (B) both convex (C) the mirror is concave and the lens is convex (D) the mirror is convex, but the lens is concave.

Answer: (A) both concave The distance from the lens to the focal point is called the focal length. For converging lenses, the focal length is... View Article

Arya, Abhimanyu and Vivek shared lunch. Arya has brought two sandwiches, one made of vegetable and one of jam. The other two boys forgot to bring their lunch. Arya agreed to share his sandwiches so that each person will have an equal share of each sandwich. (a) How can Arya divide his sandwiches so that each person has an equal share? (b) What part of a sandwich will each boy receive?

a) Since there are three people to eat, Arya should divide his sandwiches into 3 equal parts and give 1 part of each sandwich so that each person... View Article

An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the work done by the force of gravity on the object?

Answer: Work is said to be done when a force applied to an object moves that object. Work done is generally referred to in relation to the force... View Article

An object of mass 100 kg is accelerated uniformly from a velocity of 5 m s-1 to 8 m s-1 in 6 s. Calculate the initial and final momentum of the object. Also, find the magnitude of the force exerted on the object.

Answer: Initial velocity of the object (u) = 5 m/s Final velocity of the object (v) = 8 m/s Mass of the object (m) = 100 kg Time take by the... View Article

Animals are poached for illegal trading for their i) For trading them in a black market ii) Sold as exotic pets iii) Used a delicacy iv) Used for commerical purposes such as food, decor, jewelry, traditional medicines v) All of the above

All of the above... View Article

A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggests that the genetic makeup of the tall parent can be depicted as:(a) TTWW (b) TTww (c) TtWW (d) TtWw

Correct option : (c) TtWW could be the genetic makeup of the tall parent. Since half of the progenies are short, the parent plant will also have... View Article

Akhtar, Kiran and Rahul were riding in a motorocar that was moving with a high velocity on an expressway when an insect hit the windshield and got stuck on the windscreen. Akhtar and Kiran started pondering over the situation. Kiran suggested that the insect suffered a greater change in momentum as compared to the change in momentum of the motorcar (because the change in the velocity of the insect was much more than that of the motorcar). Akhtar said that since the motorcar was moving with a larger velocity, it exerted a larger force on the insect. And as a result the insect died. Rahul while putting an entirely new explanation said that both the motorcar and the insect experienced the same force and a change in their momentum. Comment on these suggestions.

The suggestion made by Kiran that the insect suffered a greater change in momentum as compared to the change in momentum of the motor car is... View Article

A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 resistances, which may be used separately, in series, or in parallel. What are the currents in the three cases?

Supply voltage, V= 220 V Resistance of one coil, R= 24Ω (i) Coils are used separately According to Ohm's law, V= I1R1 Where I1 is the... View Article

A hockey ball of mass 200 g travelling at 10 m s-1 is struck by a hockey stick so as to return it along its original path with a velocity at 5 m s-1. Calculate the change of momentum occurred in the motion of the hockey ball by the force applied by the hockey stick.

Given Mass of the hockey ball, m = 200 g = 0.2 kg Hockey ball travels with velocity, v1 = 10 m/s Find out The change of momentum occurred in... View Article

According to the third law of motion when we push on an object, the object pushes back on us with an equal and opposite force. If the object is a massive truck parked along the roadside, it will probably not move. A student justifies this by Solutioning that the two opposite and equal forces cancel each other. Comment on this logic and explain why the truck does not move.

Answer: According to the third law of motion when we push an object, the object pushes us back with an equal and opposite force. These two... View Article

Abdul, while driving to school, computes the average speed for his trip to be 20 km h-1. On his return trip along the same route, there is less traffic and the average speed is 30 km h-1. What is the average speed for Abdul’s trip?

Given that Abdul, while driving to school, computes the average speed for his trip to be 20 km h-1. On his return trip along the same route,... View Article

18 is divisible by both 2 and 3. It is also divisible by 2 x 3 = 6. Similarly, a number is divisible by 4 and 6. Can we say that the number must be divisible by 4 x 6 = 24? If not, give an example to justify your answer.

Answer: Let us consider the numbers which are divisible by 4 4, 8, 12, 16, 20, 24, 28, 32, 36, 40.... Now let us consider the numbers which... View Article

M	T	W	T	F	S	S
						1
2	3	4	5	6	7	8
9	10	11	12	13	14	15
16	17	18	19	20	21	22
23	24	25	26	27	28	29
30	31

Archives

Choose the correct option. A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each (A) two revolutions (B) One revolution (C) half revolution (D) one-fourth revolution

A taxi-driver, filled his car petrol tank with 40 liters of petrol on Monday. The next day, he filled the tank with 50 liters of petrol. If the petrol costs Rs. 44 per liter, how much did he spend in all on petrol?

A spherical mirror and a thin spherical lens have each a focal length of -15 cm. The mirror and the lens are likely to be (A) both concave (B) both convex (C) the mirror is concave and the lens is convex (D) the mirror is convex, but the lens is concave.

An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the work done by the force of gravity on the object?

An object of mass 100 kg is accelerated uniformly from a velocity of 5 m s-1 to 8 m s-1 in 6 s. Calculate the initial and final momentum of the object. Also, find the magnitude of the force exerted on the object.

Animals are poached for illegal trading for their i) For trading them in a black market ii) Sold as exotic pets iii) Used a delicacy iv) Used for commerical purposes such as food, decor, jewelry, traditional medicines v) All of the above

A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 resistances, which may be used separately, in series, or in parallel. What are the currents in the three cases?

A hockey ball of mass 200 g travelling at 10 m s-1 is struck by a hockey stick so as to return it along its original path with a velocity at 5 m s-1. Calculate the change of momentum occurred in the motion of the hockey ball by the force applied by the hockey stick.

Abdul, while driving to school, computes the average speed for his trip to be 20 km h-1. On his return trip along the same route, there is less traffic and the average speed is 30 km h-1. What is the average speed for Abdul’s trip?

18 is divisible by both 2 and 3. It is also divisible by 2 x 3 = 6. Similarly, a number is divisible by 4 and 6. Can we say that the number must be divisible by 4 x 6 = 24? If not, give an example to justify your answer.

Does phosphorus glow under black light?

Is red phosphorus illegal?

How dangerous is red phosphorus?

Why red phosphorus is used in safety matches?

What is the atomicity of phosphorus?

Which phosphorus is used in matchstick?

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