Two plates of equal areas are placed in contact wih each other. Their thickness are 2.0 cm and 5.0 cm respectively. The temperature of the external surface of the first plate is `-20^(@)C` and that of the external surface of the second plate is `20^(@)C`. What will be the temperature of the current surface if the plates (i) are of the same material, (ii) have thermal conductivities in the ratio `2:5`.

Two plates of equal areas are placed in contact with each other . Their thickness are 2 cm and 3 cm respectively. Temperature of the external surface of the first plate is -25^(@)C and that of the external surface of the second plate is 25^(@)C What will be temperature of contact surface if the plates:- (i) Are of same material (ii) Have thermal conductivity in ratio 2:3 .

Two plates of same area are placed in contact. Their thickness as well as thermal conductivities are in the ratio 2:3 . The outer surface of one plate is maintained at 10^(@) C and that of the other at 0^(@) C. What is the temperature at the common surface?

A wall consists of two layer, one of thickness 3 cm and other of 6 cm. the thermal conductivities of the materials of these layers are K and 3K respectively. The temperature of the outer surfaces of the two layers are -5^(@)C and 20^(@)C respectively. determine the temperature of the surface of contact of the two layers in the steady state.

An external force of 20 N acts at an angle of 60^(@) , with the normal to the surface of a square plate having each side of length 20 cm. What is the stress produced in the plate ?

A compound slab is made of two parallel plates of copper and brass of the same thickness and having thermal conductivities in the ratio 4:1 . The free face of copper is at 0^(@)C . The temperature of the internal is 20^(@)C . What is the temperature of the free face of brass?

The ratio of charge on left surface of plate A to the charge on the right surface of plate B is +Q +3Q -20 (A) (B) (C)

Two parallel plate air capacitors have their plate areas 100 and 500 cm^(2) respectively. If they have the same charge and potential and the distance between the plates of the first capacitor of 0.5 mm, what is the distance between the plates of second capacitor ?

Three large plates A, B and C are placed parallel to each other and charges are given as shown. The charge that appears on the left surface of plate B is

Two parallel plates A and B are joined together to form a compound plate . The thicknesses of the plate are 4.0cm and 2.5cm respectively and the area of cross section is 100cm^(2) for each plate. The thermal conductivities are K_(A)=200Wm^(-1) ^(@)C^(-1) for the palte B. The outer surface of the plate A is maintainned at 100^(@)C and the outer surface of the plate A is maintained at 100^(@)C . and the outer surface of the plate B is maintained at 0^(@)C. Find (a) the rate of heat flow through any cross section, (b) the temperature at the interface and (c) the equivalent thermal conductivity of the compound plate.