A 500mlong aluminium table expands when it was placed under the sun , it's temperature increases from 20°c to 60°c .what is the new length (linear expansivity of aluminum is 2.30*10^-5k)?

First, we need to calculate the change in temperature:

ΔT = 60°C - 20°C = 40°C

Next, we can use the formula for linear expansion:

ΔL = α * L * ΔT

Where:
ΔL = change in length
α = linear expansivity of aluminum = 2.30 * 10^-5 K^-1
L = original length = 500 mm = 0.5 m
ΔT = change in temperature = 40°C

Now, we can plug in the values:

ΔL = 2.30 * 10^-5 * 0.5 * 40
ΔL = 2.30 * 10^-5 * 0.5 * 40
ΔL = 4.60 * 10^-5 * 40
ΔL = 0.000184 * 40
ΔL = 0.00736 m

Finally, we can find the new length by adding the change in length to the original length:

New length = 0.5 + 0.00736
New length = 0.50736 m

Therefore, the new length of the aluminum table after being placed under the sun is 0.50736 meters.