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A positively-charged particle (alpha-particle) projected towards west is deflected towards north by a magnetic field. The direction of magnetic field is A) towards south B) towards east C) downward D) upward

(D) upward Explanation: Fleming’s Left-hand rule: Places the thumb, forefinger, and middle finger in mutually perpendicular directions. The finger in... View Article

Four parrots are pulled on a frictionless surface using cord .The tension in two of the cords are T2=111N T4=222N and mass of of 3 parrots are given as ,M1=12 KG M3=15kg M4=20kg .Find the mass of 2 nd parrots.

Let m be the mass of the unknown parrot. 111N = (12kg + m)a (equ.1) Following is the equation for... View Article

Choose the correct option: The magnetic field inside a long straight solenoid-carrying current. (A) is zero (B) decreases as we move towards its end (C) increases as we move towards its end (D) is the same at all points

Answer: (D) is the same at all points A coil of many circular turns of insulated copper wire wrapped closely... View Article

The traffic lights at three different road crossings change after every 48 seconds, 72 seconds and 108 seconds respectively. If they change simultaneously at 7 a.m. at what time will they change simultaneously again?

Answer: The traffic light at three different road crossings change after every 48 seconds,72 seconds, and 108 seconds, respectively. So... View Article

We know that many human activities lead to increasing levels of pollution of the air, water-bodies and soil. Do you think that isolating these activities to specific and limited areas would help in reducing pollution?

Answer: Yes, if it is limited and confined to a place then the soil and water pollution can be controlled,... View Article

A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything about whether the light eye colour trait is dominant or recessive? Why or why not?

This information is not sufficient. For considering a trait as dominant or recessive, we need data of at least three... View Article

A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? Also, find the power of the lens.

Answer: Image formed is real and inverted ∴ Magnifications (m) = -1 Since the image is real, image distance is... View Article

A truck starts from rest and rolls down a hill with a constant acceleration. It travels a distance of 400 m in 20 s. Find its acceleration. Find the force acting on it if its mass is 7 metric tons (Hint: 1 metric ton = 1000 kg).

Answer: 14000 N Given parameters Initial velocity (u) = 0 Distance travelled (s) = 400 m Time taken (t) = 20... View Article

Which of the following statements are true about alkyl halide? i) They are polar in nature. ii) Alkyl halide contain halogen atom linked to an alkyl group. iii) They undergo addition reactions. iv) They are highly soluble in water.

Alkyl halide contain halogen atom linked to an alkyl group, and they are polar in nature are true about Alkyl... View Article

Imagine that you are sitting in a chamber with your back to one wall. An electron beam, moving horizontally from back wall towards the front wall, is deflected by a strong magnetic field to your right side. What is the direction of magnetic field?

The direction of the magnetic field is vertically downwards. The current direction is from the front wall to the back... View Article

In each of the following a force, F is acting on an object of mass, m. The direction of displacement is from west to east shown by the longer arrow. Observe the diagrams carefully and state whether the work done by the force is negative, positive or zero.

Answer: Work is the product of the component of the force in the direction of the displacement and the magnitude... View Article

(a) Collect pieces of different kinds of paper. Find out which of these can be recycled.(b) With the help of a lens look at the pieces of paper you collected for the above question. Do you see any difference in the material of a recycled paper and a new sheet of paper?

(a) All types of paper can be recycled. Exceptions like plastic-coated or shiny papers are difficult to recycle. (b) It... View Article

Two objects of masses 100 g and 200 g are moving along the same line and direction with velocities of 2 m /s and 1 m /s, respectively. They collide and after the collision, the first object moves at a velocity of 1.67 m/s. Determine the velocity of the second object.

We can solve the given problem by using the law of conservation of momentum. Given Mass of one of the... View Article

A motorcar of mass 1200 kg is moving along a straight line with a uniform velocity of 90 km/h. Its velocity is slowed down to 18 km/h in 4 s by an unbalanced external force. Calculate the acceleration and change in momentum. Also calculate the magnitude of the force required.

Given: Mass of the motor car, m = 1200 kg Initial velocity of the motor car, u = 90 km/h... View Article

Name the types of following triangles: (a) Triangle with lengths of sides 7 cm, 8 cm and 9cm. (b) DABC with AB = 8.7 cm, AC = 7 cm and BC = 6cm. (c) DPQR such that PQ = QR = PR = 5cm. (d) DDEF with D = 90 (e) DXYZ with Y = 90 and XY =YZ (f) DLMN with L = 30 ,M = 70 and N =80.

Answer: A triangle is a type of polygon, which has three sides, and the two sides are joined end to... View Article

Give reasons: (a) A gas fills completely the vessel in which it is kept. (b) A gas exerts pressure on the walls of the container. (c) A wooden table should be called a solid (d) We can easily move our hand in air but to do the same through a solid block of wood we need a karate expert.

(a) A gas fills the vessel in which it is kept. Gas fills the vessel in which it is kept.... View Article

Try to construct triangles using match sticks. Some are shown here. Can you make a triangle with: (a) 3matchsticks? (b) 4matchsticks? (c) 5matchsticks? (d) 6matchsticks? (Remember you have to use all the available matchsticks in eachcase). If you cannot make a triangle, think of reasons forit.

(a) 3 matchsticks 1st side=1 matchsticks 2nd side = 1 matchsticks 3rd side=1 matchsticks. Hence, it forms an equilateral triangle.... View Article

Which statement is true from the following? i) Centriole is present in animal cell, but absent in most of the plant cells ii) Both animal cells as well as plant cells are green in colour. iii) Animal cells lack cell membranes while plant cells have cell membranes. iv) Both the cells have chloroplast

(i) Centriole is present in the animal cell but absent in most the plant cells Explanation Centrioles are the centrosome located... View Article

Represent the following numbers as integers with appropriate signs. (a) An aero plane is flying at a height two thousand meters above the ground. (b) A submarine is moving at a depth eight thousand meters below the sea level. (c) A deposit of rupees two hundred (d) Withdrawal of rupees seven hundred.

Integers are the numbers that can be positive, negative or zero, but cannot be a fraction. These numbers are used to... View Article

The statement not true about graphite is: i) The three valence electrons of carbon take part in bond formation and fourth electron is free and mobile hence can conduct electricity. ii) Graphite is denser than the diamonds iii) The thermodynamic stability of graphite is more than the diamond iv) All of these

Graphite is denser than diamond is the incorrect statement Why is diamond denser than graphite? Due to its more compact... View Article

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