What is the change in internal energy if 20 j of heat is released from a system and the system does 50 j of work on the surroundings?
a.-80 j
b.-20 j
c.80 j
d.20 j

There are weak or strong attractive forces between atoms of liquids with a high viscosity

Which configuration would produce an electric current? a) rotate a coil of copper wire between two magnets. b) connect a wire between a copper and zinc strip sitting in a beaker of water. c) connect a wire to the (+) positive end of a battery and the other end to a light bulb. d) connect a wire to the negative end of a battery and the other end to a light bulb.

What are similarities and differences between refraction, reflection, diffraction and absorption?