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.

The diagrams given below show two sound boxes A and B with wires of the same length (l) and tension (10 kgf) but different cross-sectional areas. Simultaneously, vibrating tuning forks of frequency 300 Hz are placed on boxes A and B. The paper rider falls off in case of B but not in case of A. (a) Name and explain the phenomenon responsible for the falling off of the paper rider in B. (b) The wire A resonates with a tuning fork of frequency ‘f’. Is ‘f’ greater than, less than or equal to 300 Hz? Justify your answer.

A submarine in the sea, sends an ultrasonic ping and a stopwatch is started simultaneously. The stopwatch stops on receiving the reflected wave from an obstacle and reads 1 minute 40 seconds. Calculate the distance of the obstacle from the submarine. (Speed of sound in water = 1500 m s⁻¹)

Richa weighing 40 kgf leaves point P on her skateboard and reaches point Q on the ground with velocity 10 m s⁻¹. Calculate: (a) the kinetic energy of Richa at point Q (b) the vertical height of point P above the ground. (Use g as 10 m s⁻² and neglect friction.) (c) the kinetic energy of Richa at point R. (While moving from Q to R, she loses 500 J of energy against friction.)

Three levers X, Y and Z of equal lengths are shown in the diagram. (a) Which class of lever do these belong to? (b) Among these (X, Y or Z), which one will give the maximum mechanical advantage? Justify your answer.

(a) Name the radiations: (1) for which a quartz prism is used to study the spectrum. (2) which are used in remote sensing devices. (3) which are used in traffic signals in India. (b) Name one property common to all electromagnetic radiations.

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.

(a) A certain amount of heat will warm 1 g of material X by 10°C and 1 g of material Y by 40°C. Which material has higher specific heat capacity? (b) Which material, X or Y, would you select to make a calorimeter? (c) The specific heat capacity of a substance remains the same when it changes its state from solid to liquid. State True or False.