n) Determine the fractional change in length of a brass bar when its temperature is reduced from 90oC to 15oC.o) A copper bar has a length of 1.2 m and a cross-sectional area of 5.0x10?4 m2 One end is held at a temperature of 100oC and the other at 0oC.Calculate how much heat is transferred along the bar per second
The clothes probably won't whiten. Try hydrogen peroxide in an inconspicuous place. I wanted to know how you are storing them. Plastic will yellow your clothes over time.
You can purchase products on the market that do that for you but be careful to read their labels before you buy them so that you get the right one for your fabrics.
That is exactly what bleach is designed for.
n) (fractional change in length) (thermal expansion coeff. for brass)x(change in temperature) You'll find the thermal expansion coeff. for brass at the bottom of your exam paper. so the fractional change in length is (1.8 x 10^-6)(90-15)0.000135% o) Q/t KA(ΔT)/l where Q/t is heat transfer per second, K is the thermal conductivity of copper, A is cross-sectional area, ΔT is change in temp and l is length so (398)x(5x10^-4)x(100)/(1.2)16.583 J/s Learn all the heat questions, there's always a long question on heat every year. Good luck in your exam tomorrow :)
brass linear expansion coefficient λbr 19*10^-6 °C^-1 ΔL 100*λbr*ΔT 10^2*19*10^-6*0.75*10^2 0.75*19*10^-2 0.1425% Q k*A*(T2-T1)/d 3,50*10^2*5*10^-4*10^2/1.2 14.6 watt
