You are provided with unknown mass “m”, a knife edge, 50 g mass, 100 g mass, and a metre rule. Perform experiment through the following procedures: (a) Find and mark the centre of gravity C of the metre rule AB by balancing it freely on a knife edge. (b) Place a metre rule on a knife edge at its centre of gravity C. (c) Suspend the 100 g mass at point x=10 cm from the centre of gravity of a metre rule. Suspend 50 g mass at distance a =5 cm from C on the other side of C. (d) Suspend the mass m to the side of 50 g mass and adjust it until the metre rule balances horizontally as shown in the following Figure. (e) Repeat the procedure in 1 (d) when x =15 cm, 25 cm and 30 cm. Find the corresponding value of y (cm) in each experiment. Answer the following questions:

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Determine the e.m.f of the cell and the resistance of a given piece of wire through the following procedures: (a) Connect the circuit diagram as shown below in which E is a battery, K is a key, L is the length of the wire, R is the resistance box and A is an ammeter. (b) With L = 12 cm and R set at 1 , record the ammeter reading I (A). (c) Without altering the value of L, repeat the procedure in 2 (b) with R = 2 Ω, 3 Ω, 4 Ω and 5 Ω. Record the corresponding values of ammeter reading in each case.

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