(a) Calculate the effective resistance across AB :(b) (i) State whethe

1.	(a) Calculate the effective resistance across AB :(b) (i) State whether the specific heat capacity of a substance remains the same when its state changes from solid to liquid. (ii) Give one example to support your answer. (c) A magnet kept at the centre of two coils A and B is moved to and fro as shouni in the diagram. The two galvanometers show deflection. State with a reason whether : x > y or x <y [x and y are magnitudes of deflection] (d) (i) Why is a nuclear fusion reaction called a thermo nuclear reaction? (ii) Complete the reaction : 3 He2 + 2H1→ 4He2 +…….+Energy (e) State two ways to increase the speed of rotation of a DC motor.
Answer» (a) Resistors of 5 Ω and 4 Ω are in series, therefore, their net resistance is Rs = 5 + 4 = 9 Ω. Now, this 9 Cl and 3 Ω are in parallel, hence net resistance R_p=93/9+3=18/12=1.5Ω Now, this is in series with the 8 Cl resistor, hence net resistance of the circuit is RT = 8 + 1.5 = 9. 5 (b)* (i) No, specific heat capacity does not remain the same when it changes from solid to liquid. (ii) Let us take the example of water. Specific heat capacity of water = 4.2 J kg^-1 K^-1 and specific heat capacity of ice = 2.1 J kg^-1K^-1 (c) x < y. This is because coil B has more number of turns. (d) (i) Because this occurs at a very high temperature. (ii) ³He₂ + ²H₁→ ⁴He₂ + ^₁H₁ + Energy (e) The two ways are 1. Strong magnet and 2. High current.

(a) Calculate the effective resistance across AB :(b) (i) State whether the specific heat capacity of a substance remains the same when its state changes from solid to liquid. (ii) Give one example to support your answer. (c) A magnet kept at the centre of two coils A and B is moved to and fro as shouni in the diagram. The two galvanometers show deflection. State with a reason whether : x > y or x <y [x and y are magnitudes of deflection] (d) (i) Why is a nuclear fusion reaction called a thermo nuclear reaction? (ii) Complete the reaction : 3 He2 + 2H1→ 4He2 +…….+Energy (e) State two ways to increase the speed of rotation of a DC motor.

Answer»

(a) Resistors of 5 Ω and 4 Ω are in series, therefore, their net resistance is Rs = 5 + 4 = 9 Ω.

Now, this 9 Cl and 3 Ω are in parallel, hence net resistance

R_p=9*3/9+3=18/12=1.5Ω

Now, this is in series with the 8 Cl resistor, hence net resistance of the circuit is RT = 8 + 1.5 = 9. 5

(b) (i) No, specific heat capacity does not remain the same when it changes from solid to liquid.

(ii) Let us take the example of water.

Specific heat capacity of water = 4.2 J kg^-1 K^-1

and specific heat capacity of ice = 2.1 J kg^-1K^-1

(c) x < y. This is because coil B has more number of turns.

(d) (i) Because this occurs at a very high temperature.

(ii) ³He₂ + ²H₁→ ⁴He₂ + ^₁H₁ + Energy
(e) The two ways are

1. Strong magnet and

2. High current.