The capacitance of a capacitor between` 4//3` times its original value if a dielectric slab of thickness `t=d//2` is inserted between the plates (d is the separation between the plates). What is the dielectric consant of the slab?

Explanation

`(epsilon_(0)A)/([d-(d)/(2)+(d)/(2k)])=(4)/(3)(epsilon_(0)A)/(d)`
or `(1)/((d)/(2)(1+(1)/(K)))=(4)/(3d)`
on solving we get `K=2`