Hi:) anyone able to explain what’s human reaction time in physics ? Thank you in advanced :)

Select the correct answer. brian is repairing an old alarm clock. he needs to replace a device that converts the electric energy into sound energy. which of these devices should he use? a. battery b. buzzer c. motor d. switch

Awave is produced in a rope. the wave has a speed of 33 m/s and a frequency of 22 hz.

Red light strikes a metal surface and electrons are ejected. if violet light is now used with a 10% greater intensity, what will happen to the ejection rate (number of ejected electrons per second) and the maximum energy of the electrons? a) greater ejection rate; same maximum energyb) same ejection rate; greater maximum energyc) greater ejection rate; greater maximum energyd) same ejection rate; same maximum energye) none of the above answers are correct