The variation in length of a substance along three principal directions, with temperature is shown in the fig . The average superficial expansivity of the substance is

The variation in length of a substance along three principal direction

1.	The variation in length of a substance along three principal directions, with temperature is shown in the fig . The average superficial expansivity of the substance is
Answer» `40.00 XX 10^(-5)//°C` `26.67 xx 10^(-5)//°C` `13.33 xx 10^(-5)//°C` `30.93 xx 10^(-5)//°C` ANSWER :B