The heat current is written as `(DeltaQ)/(Deltat)` . Why don't we write `(dQ)/(dt)` ?

The drift speed is defined as v_(d)=(Delta l//Delta t) where (Delta l)is the distance drifted in a long time (Delta t). Why don't we define the drift speed as the limit of (Delta l//Delta t) as (Delta t (rarr)0)?

A warning of high voltage is usually displayed instead of high current near an electrical equipment or transmission lines but it is actually the current that surges through a body in contact with the equipement . Why don't we rather use the warnings of high current ?

Assertion : Specific heat of any substance remains constant at all temperatures. Reason : It is given by s= 1/m * (dQ)/(dt) .

The two ends of a rod of length L and a uniform cross-sectional area A are kept at two temperature T_(1) and T_(2) (T_(1) gt T_(2)) . The rate of heat transfer. (dQ)/(dt) , through the rod in a steady state is given by

If electromagnetic radiation is made up of quanta, why don't we detect the discrete packets of energy, for example, when we listen to a radio?

The molar specific heat of a gas is defined as C=(Dq)/(ndT) Where dQ =heat absorbed n = mole number dT = change in temperature The equation of the above process in the variables T ,V is