If two metallic plates of equal thickness and thermal conductivities `K_(1)` and `K_(2)` are put together face to face and a common plate is constructed, then the equivalent thermal conductivity of this plate will be

If K is thermal conductivity then resisitivity will be-

A composite slab is prepared by pasting two plates of thickness L_(1) and L_(2) and thermal conductivities K_(1) and K_(2) . The slab have equal cross-sectional area. Find the equivalent conductivity of the composite slab.

A composite slab is prepared by pasting two plates of thickness L_(1) and L_(2) and thermal conductivities K_(1) and K_(2) . The slab have equal cross-sectional area. Find the equivalent conductivity of the composite slab.

A composite slab is prepared by pasting two plates of thickness L_(1) and L_(2) and thermal conductivites K_(1) and K_(2) . The slab have equal cross-sectional area. Find the equivalent conductivity of the composite slab.

Two rods of length l and 2l thermal conductivities 2K and K are connected end to end. If cross sectional areas of two rods are eual, then equivalent thermal conductivity of the system is .

Two identical plates with thermal conductivities K and 3K are joined together to form a single plate of double thickness. The equivalent thermal conductivity of one composite plate so formed for the flow of heat through its thickness is.

Two identical plates with thermal conductivities K and 3K are joined together to form a single plate of double thickness. The equivalent thermal conductivity of one composite plate so formed for the flow of heat through its thickness is.