WAEC - Physics (2009 - No. 38)
A wire of resistivity 4.40 x 10-5\(\Omega\) cm has a cross sectional area of 7.50 x 10-4 cm2. Calculate the length of the wire that will be required to make a 4.0\(\Omega\) resistor
82.50 cm
68.18cm
15.90cm
11.95cm
คำอธิบาย
L = \(\frac{R.A}{e} = \frac{4 \times 7.50 \times 106{-4}}{4.40 \times 10^{-5}} = 68.18cm\)