Which valve is located between the right atrium and the right ventricle?

$A$ magnetic needle lying parallel to a magnetic field is turned through $60^{\circ}$. The work done on it is $W$. The torque required to maintain the magnetic needle in the position mentioned above is

Three houses are available in a locality. Three persons apply for the houses. Each applies for one house without consulting others. The probability that all the three apply for the same house is

$A$ cylinder of radius $R$ made of a material of thermal conductivity $K_1$ is surrounded by a cylindrical shell of inner radius $R$ and outer radius $2R$ made of material of thermal conductivity $K_2$. The two ends of the combined system are maintained at two different temperatures. There is no loss of heat across the cylindrical surface and the system is in steady state. The effective thermal conductivity of the system is

How many types of lichens are there based on their external morphology (growth form)?

The correct statements $(s)$ about intermolecular forces is$(are)$
$(A)$ The potential energy between two point charges approaches zero more rapidly than the potential energy between a point dipole and a point charge as the distance between them approaches infinity.
$(B)$ The average potential energy of two rotating polar molecules that are separated by a distance $r$ has $1 / r^3$ dependence.
$(C)$ The dipole-induced dipole average interaction energy is independent of temperature.
$(D)$ Nonpolar molecules attract one another even though neither has a permanent dipole moment.