Work, Energy and Power Class 11 Notes Physics Chapter 6 Work, Energy and Power Class 11 Notes Physics Chapter 6 • Work is said to be done when a force applied on the body displaces the body through a certain distance in the direction of applied force. It is measured by the product of the force and the distance moved in the direction of the force, i.e., W = F-S • If an object undergoes a displacement ‘S’ along a straight line while acted on a force F that makes an angle 0 with S as shown. The work done W by the agent is the product of the component of force in the direction of displacement and the magnitude of displacement. • If we plot a graph between force applied and the displacement, then work done can be obtained by finding the area under the F-s graph. • If a spring is stretched or compressed by a small distance from its unstretched configuration, the spring will exert a force on the block given by F = -kx, where x is compression or elongation in spring, k is a constant called s
Structure of Atom Class 11 Notes Chemistry Chapter 2 Structure of Atom Class 11 Notes Chemistry Chapter 2 • Discovery of Electron—Discharge Tube Experiment In 1879, William Crooks studied the conduction of electricity through gases at low pressure. He performed the experiment in a discharge tube which is a cylindrical hard glass tube about 60 cm in length. It is sealed at both the ends and fitted with two metal electrodes as shown in Fig. 2.1. The electrical discharge through the gases could be observed only at very low pressures and at very high voltages. The pressure of different gases could be adjusted by evacuation. When sufficiently high voltage is applied across the electrodes, current starts flowing through a stream of particles moving in the tube from the negative electrode (cathode) to the positive electrode (anode). These were called cathode rays or cathode ray particles. • Properties of Cathode Rays (i) Cathode rays travel in straight line. (ii) Cathode rays start from cat