CBSE ADDA

CBSE ADDA 1. Calculate the resistance of a copper wire of length 1 m and area of cross section 2 mm2. Resistivity of copper is1 7 10−8 m n Solution : R= 1A=(1 7 10−8 m) 1m2 (10−3m)=8 5 10−3 2.Calculate the potential difference across each resistor in the circuit shown in Figure 5.W2. Solution : The three resistors are joined in series. Their equivalent resistance is Req=4 +6f +10 =20 The current through the cell is i = V520 =0 25A The same current passes through each resistor.  Using Ohm's law, the potential difference across the 4-£1 resistor = 025A 4 =1V across the 6-Q resistor = 0 25A 6 =1 5V and across the 10-0 resistor = 0 25A 10 =2 5V 3. Consider the circuit shown in Figure 5.W4. The voltmeter on the left reads 10 V and that on the right reads 8 V.  Find (a) the current through the resistance R,  (b) the value of K and  (c) the potential difference across the battery. Solution : (a) Apply Ohm's law to the 4-Q resistor.  The curre...