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A person is unable to see objects nearer than 50cm. He wants to read a book placed at a distance of 25cm. Find the nature of focal length and power of the lens, he needs for his spectacles.

A person is unable to see objects nearer than 50cm. He wants to read a book placed at a distance... View Article

Three bulbs A, B and C are connected as shown in the figure. The bulbs B and C are identical. If bulb C is fused, then (1) Brightness of both bulbs A and B will increase (2) Brightness of both bulbs A and B will decrease (3) Brightness of bulb A decrease and that of bulb B increases (4) None of the bulbs will glow

Answer:(3) Brightness of bulb A decrease and that of bulb B increases Bulbs B and C are connected in parallel... View Article

About which of the following axes moment of inertia of a circular disc is minimum? (1) Axis passing through its centre and perpendicular to its plane. (2) Axis along the diameter. (3) Axis along the tangent and in its own plane (4) Axis along the tangent and perpendicular to its plane.

Answer: (2) Axis along the diameter Moment of inertia is defined as the quantity expressed by the body resisting angular... View Article

An object at a distance of 30 cm from a concave mirror gets its image at the same point. The focal length of the mirror is (1) -30cm (2) +30cm (3) -15cm (4) +15cm

Answer: (3) -15cm If a hollow sphere is cut into parts and the outer surface of the cut part is... View Article

A conducting sphere of radius r = 20 cm is given a charge q = 16μC. What is electric field E at its centre?

Answer: Given parameters Radius of the sphere (r) = 20cm = 0.2 m Charge (q) = 16μC = 16 ×... View Article

A hot and a cold body are kept in vacuum separated from each other. Which of the following causes decrease in temperature of the hot body? (1) Radiation (2) Convection (3) Conduction (4) Temperature remains unchanged.

Answer: (3) Radiation In the radiation mode, heat can pass through a vacuum, reducing the temperature of the hot body.... View Article

What happens to the centripetal acceleration of a revolving body if you double the orbital speed v and half angular velocity ω (1) It remains unchanged (2) It is halved (3) It is doubled (4) It is quadrupled

Answer: (1) It remains unchanged Centripetal acceleration is defined as the property of the motion of an object, traversing a... View Article

In the adjoining figure, AOB is a straight line. Find the value of x. Hence, find ∠AOC, ∠COD and ∠BOD

From the figure we know that ∠BOD and ∠AOD are a linear pair of angles Hence ∠BOD + ∠AOD = 180º... View Article

In the absence of an electric field, the mean velocity of free electrons in a conductor at absolute temperature (T) is

In the absence of an electric field, the mean velocity of free electrons in a conductor at absolute temperature (T)... View Article

Moment of inertia of a rectangular plate about an axis passing through p and perpendicular to the plate is

Moment of inertia is defined as the quantity expressed by the body resisting angular acceleration which is the sum of... View Article

How to find to find the mean, mode, and median of any set of numbers.

Mean Mean is the most commonly used measure of central tendency. It actually represents the average of the given collection... View Article

Let us consider a system of units in which mass and angular momentum are dimensionless. If length has dimension of L, which of the following statement(s) is/are correct? (A) The dimension of force is L^–3 (B) The dimension of power is L^–5 (C) The dimension of linear momentum is L^–1 (D) The dimension of energy is L^–2

The correct options are (A) The dimension of force is L–3 (C) The dimension of linear momentum is L–1 (D)... View Article

Assuming the balls to be identical except for difference in colours the number of ways in which one or more balls can be selected from 10 white, 9 green and 7 black balls is

Permutation relates to the act of arranging all the members of a set into some sequence or order. The combination is... View Article

A card is drawn from a well shuffled deck of 52 cards. what is the probability of getting a red queen card

Probability is the measurement of chances – the likelihood that an event will occur. If the probability of an event... View Article

The coefficient of friction of a surface is 1/√3. what should be the angle of inclination so that a body placed on the surface just begins to slide down?

Coefficient of friction The coefficient of friction is defined as the ratio of the force of friction acting between two... View Article

If two interior angles on the same sides of a transversal intersecting two parallel lines are in the ratio 2 3 ,then the smaller of the two angles is

The angles which are formed inside the two parallel lines, when intersected by a transversal, are equal to its alternate pairs. These... View Article

An electron is travelling horizontally towards the east. A magnetic field in a vertically downward direction exerts a force on the electron along____ (a) East (b) West (c) North (d) South

The correct answer is (d) South Solution The force experienced will be in the south direction. Fleming’s left-hand rule is used to... View Article

A spring is kept compressed by a toy car of mass 150g. On releasing the car, it moves with a speed of 0.2ms−1. So, the elastic potential energy of the spring is

Given According to the given data m=150g=150×10−3kg v=0.2ms−1 Find out We have to determine the elastic potential energy of the spring ... View Article

When a transversal intersects two parallel lines, the corresponding angles so formed will be ________

When a transversal intersects two parallel lines, the corresponding angles so formed will be equal Solution Corresponding angles are the angles... View Article

Let a, b, c, d and p be any non zero distinct real numbers such that (a²+b²+c²)p²-2(ab+bc+cd)p +(b² +c²+d²) = 0. Then
1) a, c, p are in G.P. 2) a, b, c, d are in G.P. 3) a, b, c, d are in A.P. 4) a, c, p are in A.P.

The correct answer is 2) a, b, c, d are in G.P. Solution Let us solve the given equation (a2+b2+c2)p2-2(ab+bc+cd)p... View Article

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