The temperature of a well stirred liquid kept open to a cold surroundings is plotted against time. (Assume conditions favorable to Newton's law of cooling) The value of `sec^2theta_1` is

The correct graph between the temperature of a hot body kept in cooler surrounding and time is (Assume newton's law of cooling)

In the circuit shown the resistance R is kept in a chamber whose temperature. is 20^(@) C which remains constant. The initial temperature and resistance of R is 50^(@)C and 15 Omega respectively. The rate of change of resistance R with temperature is (1)/(2)Omega//^(@)C and the rate of decrease of temperature of R is In (3//100) times the temperature difference from the surrounding (Assume the resistance R loses heat only in accordance with Newton's law of cooling) If K is closed at t = 0, then find the (a) value of. R for which power dissipation in it is maximum. (b) temperature of R when power dissipation is maximum (c) time after which the power dissipation will be maximum

A liquid in a beaker has temperature theta(t) at time t and theta_0 is temperature of surroundings, then according to Newton's law of cooling the correct graph between log_e( theta-theta_0) and t is :

A body with an initial temperature theta_(1) is allowed to cool in a surrounding which is at a constant temperature of theta_(0) (theta lt theta_(1)) Assume that Newton's law of cooling is obeyed Let k = constant The temperature of the body after time t is best experssed by .

One end of a rod length 20cm is inserted in a furnace at 800K. The sides of the rod are covered with an insulating material and the other end emits radiation like a blackbody. The temperature of this end is 750K in the steady state. The temperature of the surrounding air is 300K. Assuming radiation to be the only important mode of energy transfer between the surrounding and the open end of the rod, find the thermal conductivity of the rod. Stefan constant sigma=6.0xx10^(-1)Wm^(-2)K^(-4) .

One end of a rod length 20cm is inserted in a furnace at 800K . The sides of the rod are covered with an insulating material and the other end emits radiation like a blackbody. The temperature of this end is 750K in the steady state. The temperature of the surrounding air is 300K . Assuming radiation to be the only important mode of energy transfer between the surrounding and the open end of the rod, find the thermal conductivity of the rod. Stefan constant sigma=6.0xx10^(-1)Wm^(-2)K^(-4) .

A simple pendulum made of bob of mass m and a metallic wire of negligible mass has time period 2 s at T = 0^(@)C . If the temperature of the wire is increased and the corresponding change in its time period is plotted against its temperature, the resulting graph is a line of slope S . If the coefficient of linear expansion of metal is alpha then value of S is :

Instantaneous temperature difference between cooling body and the surroundings obeying Newton's law of cooling is theta . Which of the following represents the variation of In theta with time t?

A body cools in a surrounding which is at constant temperature of theta_(0) . Assume that it obeys Newton's law of colling. Its temperature theta is plotted against time t . Tangents are drawn to the curve at the points P(theta=theta_(t)) and Q(theta=theta_(2)) . These tangents meet the time axis at angles of phi_(2) and phi_(1) , as shown

One end of a rod of length 20cm is inserted in a furnace at 800K The sides of the rod are covered with an insulating material and the other end emits radiation like a black body. The temperature of this end is 750K in the steady state The temperature of the surrounding air is 300K Assuming radiation to be the only important mode of energy transfer between the surrounding and the open end of the rod, find the thermal conductivity of the rod Stefan's constant sigma = 6.0 xx 10^(-8) W m^(-2) K^(-4) .