A non-uniform kite is hanging freely from the branch of a tree as shown. Study the figure and answer the following: (a) Fill in the blank. ............... [P, Q, R or S] is the most probable position of its centre of gravity. (b) Support your answer to (a) with a reason.

A ray of light enters a rectangular glass slab submerged in water at an angle of incidence 55°. Does this ray undergo total internal reflection when it moves from water to glass? Justify your answer. (The critical angle for glass–water interface is 54°)

Calculate the amount of heat absorbed by 200 g of paraffin wax to melt completely at its melting point. [Specific latent heat of fusion of paraffin wax = 146 J g⁻¹]

(a) Which of the two, alternating current or direct current, produces a varying magnetic field when it flows through a conductor? (b) State the frequency of the alternating current supply in India.

Which among the following is a vector quantity? (a) work (b) power (c) energy (d) moment of couple

A body is acted upon by two equal and opposite forces, that are NOT along the same straight line. The body will : (a) remain stationary (b) have only rotational motion (c) have only rectilinear motion (d) have both rectilinear and rotational motion

A copper rod PQ carrying current is kept in a magnetic field as shown in the diagram. (a) The copper rod PQ will move towards C. State True or False. (b) Name the law used to determine the direction of motion of PQ. (c) What will be the effect on the force experienced if rod PQ is replaced by another copper rod of the same length but greater cross-sectional area? (d) Justify your answer in (c).

Three identical bulbs B1, B2 and B3, each of power rating 18 W, 12 V, are connected to a battery of 12 V as shown. (a) Calculate: (i) the resistance of each bulb (ii) the current drawn from the cell (b) If bulb B3 is removed from the circuit, will the brightness of bulb B1 increase, decrease or remain the same?

Study the reaction given below and answer the questions that follow: (a) Name the process depicted in the reaction. (b) What is the value of X represented by the mass number of the intermediate uranium nucleus? (c) Identify Y, the missing product of the reaction.

Two rays PQ and RS are incident on a rectangular glass block as shown in the diagram. Observe the diagram and answer the questions that follow. Which of these two rays will: (a) have greater lateral displacement on emerging out of the block? (b) travel with greater speed in the block? (c) scatter more in the atmosphere?

(a) Out of the three rays (I, J, H) shown in the diagram, which ray will suffer Total Internal Reflection while inside the prism? (Critical angle of the prism is 42°.) (b) Copy the diagram to complete the path of the ray which you have named in (a) till it comes out of the prism.

Curium is a radioactive element with the symbol named in honour of Madam Curie. The graph of number of protons vs number of neutrons for some elements is shown below: (a) Which point on the graph indicates the element Cm? (b) Which point on the graph indicates daughter nucleus after Cm undergoes radioactive decay of 1α followed by 2β? (c) State the mass number of the daughter nucleus.