DS = ER DS cosq  = ER DS,   since q = 0°
   = ERa2
Net flux through the cube
Rationalised 2023-24
32
Physics
 EXAMPLE 1 11
 EXAMPLE 1 10
= fR + fL = ERa2 – ELa2 = a2 (ER – EL) = aa2 [(2a)1/2 – a1/2]
=  aa5/2 (
)
2 – 1
=  800 (0 1)5/2 (
)
2 – 1
= 1