The filament of light bulb operates at 2000K it has a diameter of 0.80mm and is made of metal of emissivity 0.5. What is the length of filament is needed if the power of the ball is to be 100W. ( stefan's constant= 5.67×10^-8)​

What happens when chlorine reacts with bromine? a. electrons move from the chlorine atoms to the bromine atoms. b. electrons move from the bromine atoms to the chlorine atoms. c. electrons are shared between the chlorine atoms and the bromine atoms. d. electrons become delocalized among the atoms.

Arowboat passenger uses an oar to push the boat off the dock by exerting a force of 40n for 3.0s. what impulse acts on the boat.

The electric field direction is defined by the direction of the force felt by (select one of the following answers): 1. a negative charge. 2. a positive charge. 3. both positive and negative charges.