A liquid fills a horizontal capillary tube whose one end is dipped in a large pool of the liquid. Experiments show that the distance $L$ travelled by the liquid meniscus inside the capillary in time $t$ is given by

$L = k \gamma^a R^b \mu^c \sqrt{t},$

where $ \gamma $ is the surface tension, $ R $ is the inner radius of the capillary, and $ \mu $ is the dynamic viscosity of the liquid. If $ k $ is a dimensionless constant, then the exponent $ a $ is _______ (rounded off to 1 decimal place).

Viscosity of the fluid $$\mu = 0.44\,\,kg/m$$-$$s$$ and density $$\rho = 888$$ $$kg/{m^3}.$$