The is the middle layer of earth's atmosphere.
a. exosphere
b. troposphere
c. mesosphere
d. stratosphere

Which type of current is produced by a wire breaking magnetic field lines and changing the polarity? a. alternating b. direct c. straight d. alternating and direct

Calculate the mass of an object that has a momentum of 100kg x m/sec and velocity of 4 m/sec

Two polarizers are oriented at 70∘∘ to one another. unpolarized light falls on them. what fraction of the light intensity is transmitted?