# Physics,

GK -Physics

1-A perfect black body is one which absorbs heat radiations of all wave lengths falling on it

2-The highest thermal diffusivity is of LEAD.

3-During a refrigeration cycle, heat is rejected by the refrigerant in a condenser.

4-Thermal conductivity of water may increase or decrease depending upon temperature with rise in temperature.

5-The thickness of thermal and hydrodynamic boundary layer is equal if Prandtl number is equal to one.

6-For ammonia refrigerating systems, the tubes of a shell and tube condenser are made of steel.

7-The optimum effective temperature for human comfort is lower in winter than in summer

8-A refrigeration system removes heat from a low temperature body and delivers it to a high temperature body

9-The heat transfer takes place according to Second law of thermodynamics

10-Thermal diffusivity is a physical property of a substance

11-The difference between dry bulb temperature and wet bulb temperature, is called wet bulb depression.

12-The inversion of a mechanism is obtained by fixing different links in a kinematic chain

13-When the speed of the engine fluctuates continuously above and below the mean speed, the governor is said to be hunt.

14-The motion on a curved path, when one component of velocity is constant and the other is variable is called Projectile motion

15-Kicked or thrown balls, jumping animals, object thrown from a window, a missile shot from a gun, a bomb released from a bomber plane, etc are all example of Projectiles

16-To attain maximum range, the projectile must be launched at an angle of 45°

17-Any object that is given any initial velocity and which follows a path due to gravitational force acting on it and by the frictional resistance of the atmosphere is called  Projectile

18-The projectile motion and circular motion are good example of Two dimension motion.

19-The motion of a projectile follows a curved path.

20-A player making a long jump is an example of Projectile motion.