ICSE Books Solutions

Selina Concise Physics Class 9 ICSE Solutions Propagation of Sound Waves Selina ICSE Solutions for Class 9 Physics Chapter 8 Propagation of Sound Waves Exercise 8(A) Solution 1S. Sound is caused due to vibrations of a body. Solution 2S. Sound is a form of energy that produces the sensation of hearing in our ears. Sound is produced by a vibrating body. Solution 3S. Vibrating Solution 4S. Experiment: A tuning fork is taken and its one arm is struck on a rubber pad and it is brought near a tennis ball suspended by a thread as shown in figure. It is noticed that as the arm of the vibrating fork is brought close to the ball, it jumps back and forth and sound of the vibrating tuning fork is heard. When its arm stop vibrating, the ball becomes stationary and no sound is heard. Solution 5S. Experiment to demonstrate that a material medium is necessary for the propagation of sound: An electric bell is suspended inside an airtight glass bell jar. The bell jar is connected to a vacuum pump as sho

Selina Concise Physics Class 9 ICSE Solutions Reflection of Light Selina ICSE Solutions for Class 9 Physics Chapter 7 Reflection of Light Exercise 7(A) Solution 1S. The return of light into the same medium after striking a surface is called reflection. Solution 2S. Black silvered surface reflects most of the light incident on it. Solution 3S. (a) Plane mirror: Plane mirror is a highly polished and smooth reflecting surface made from a clear plane glass sheet, usually thin and silvered with suitable reflecting abrasive (for example, mercury) on one side. Once this pasting is done, then the glass becomes opaque but due to the reflecting property of the abrasive, the plane glass sheet becomes a plane glass reflector or a plane glass mirror. (b) Incident ray: The light ray striking a reflecting surface is called the incident ray. (c) Reflected ray: The light ray obtained after reflection from the surface, in the same medium in which the incident ray is travelling, is called the reflected r