What is threshold stimulus?

Define the following terms. (i) Resting potential (ii) Action potential (iii) Threshold stimulus / potential

Define: Threshold stimulus:

Light of frequency 7.21 xx 10^14 Hz is incident on a metal surface. Electrons with a maximum speed of 6.0 xx 10^5 ms^-1 are ejected from the surface. What is the threshold frequency for photoemission of electrons?

Given the following data for incident wavelength , and the stopping potential obtained from an experiment on photoelectric effect , estimate the value of Planck's constant and the work function of the cathode material. What is the threshold frequency and corresponding wavelength? What is the most likely metal used for emitter? Incident wavelength (in overset (@)(A) ) 2536, 3650 Stopping potential (in V) 1.95 , 0.5

What is photoperiodic stimulus?

Define stimulus

Assertion: Muscle contraction force increases with rise in strength of stimulus. Reason: This is due to increased contraction of individual muscle fibers with increase in stimulus strength.