A block of mass 10 kg placed on rough horizontal surface having coefficient of friction = 0.5, if a horizontal force of 100 N acting on it then acceleration of the block will be : -

The correct option is B 5 m/s${}^2$
In horizontal direction, two forces are acting on the block : 100 N force and friction force (f)

f=$\mu N=\mu mg=0.5\times 10\times 10=50N$

So, net force acting on the block in horizontal direction = 100 N-50 N = 50 N

acceleration of the block = Net force / mass of block = 50 N/10 kg = 5 $m{s}^{-2}$