Physics Paper 3 WASSCE (SC), 2020

Alternative B

 

Question 3B

 

 

(b)        (i)         State the four factors that affect the resistance of a wire.

(ii)        A 2 Ω resistor is connected in parallel with a resistor of resistance R. If the p.d. across R is 1.2 V and the same amount of current of 0.6 A flows through R and the 2 Ω resistor, determine the value of R.

Observation

 

 

Part (b) Candidates response was satisfactory.

 

The expected response:

 

(b)     (i)            Factors that affect the resistance of a wire
                                    -           length of wire
                                    -           cross-sectional area//thickness/diameter of the wire
                                    -           nature/material of the wire/resistivity
                                    -           temperature                                                                                                    
                        (ii)        Determination of the value of R

                                    R = r              

                                    R = r             

                                        = 2 W