Aim	To verify the laws of reflection of sound.
Apparatus Required	Two highly polished metal tubes made up of stainless steel or aluminum of length 25 cm and diameter 2 cm, a drawing sheet, metal plate, a geometrical set, thumb pins, drawing board/table, stopwatch, metal stand.
Theory	Sound: Sound is a form of energy that travels through matter in the form of waves. These waves are created when an object vibrates, such as when a guitar string is plucked or when someone speaks. The waves travel through the air, and when they reach our ears, they cause our eardrums to vibrate, which our brains then interpret as sound. Sound waves can be characterized by a few different properties. One of these is frequency, which refers to how many waves pass a given point in a certain amount of time. Frequency is measured in Hertz (Hz), and higher frequencies correspond to higher-pitched sounds. Another property of sound waves is amplitude, which refers to the height of the waves. Amplitude is measured in decibels (dB), and higher amplitudes correspond to louder sounds. Sound can be used for a variety of purposes, including communication, entertainment, and scientific research. It is also an important aspect of music, which is created by manipulating sound waves in specific ways to produce pleasing and harmonious combinations of sound. Reflection of sound: Reflection of sound refers to the phenomenon in which sound waves bounce off surfaces and change direction. When a sound wave encounters a surface, some of the wave’s energy is absorbed by the surface, while the rest is reflected back into the surrounding environment. The reflection of sound waves can have a significant impact on the way we perceive sound in a given space. For example, in a room with hard surfaces like walls, floors, and ceilings, sound waves will bounce off these surfaces and create echoes, which can make it difficult to hear speech or music clearly. This is why many performance spaces and recording studios are designed with sound-absorbing materials like foam or acoustic tiles, which help to reduce the amount of reflection and improve the clarity of the sound. The way sound waves reflect off surfaces is influenced by several factors, including the size and shape of the surface, the angle at which the sound wave hits the surface, and the properties of the material the surface is made of. These factors can be manipulated to control the reflection of sound waves in a given space, which can be useful in designing spaces for specific acoustic purposes. For example, in a concert hall, the shape and placement of the walls and ceiling can be designed to create a particular sound quality that enhances the experience of the music.
Laws of Reflection of sound	The laws of reflection of sound are similar to the laws of reflection of light and describe how sound waves reflect off surfaces. There are two main laws of reflection of sound: 1 . The angle of incidence is equal to the angle of reflection: This means that when a sound wave hits a surface, it will bounce off at the same angle as the angle at which it hit the surface. This law applies regardless of the shape or size of the surface. 2 . The incident wave, the reflected wave, and the normal to the surface all lie in the same plane: This means that when a sound wave hits a surface, the incident wave, the reflected wave, and an imaginary line perpendicular to the surface (known as the normal) will all lie in the same plane. Together, these laws dictate how sound waves will bounce off surfaces and can be used to predict the behavior of sound in different environments. For example, in a room with flat walls, the laws of reflection of sound can be used to determine how sound waves will bounce off the walls and create echoes. In contrast, in a room with curved walls or other irregular shapes, the behavior of sound waves may be more complex and require more advanced mathematical modeling.

Procedure

1 .Attach the white sheet securely onto the drawing board using a thumb pin. 2 .Sketch a line AB to indicate the placement of the metal plate as the reflecting surface, and use a metal stand to draw normal line OP perpendicular to line AB. Refer to the figure for guidance. 3 .Sketch line OC at a 30° angle to line OP. 4 .Position the metal tube close to point O of the normal line and place the metal plate on line OC. 5 .Place the ticking watch near one end of the metal tube. 6 .Position the second metal tube so that one end is near point O. 7 .Move your ear near the other end of the tube and adjust its position until it captures the sound. 8 .Mark the position of the tube when it collects the clear and maximum reflected sound. 9 . Draw an extended line of reflected sound wave and mark it as OD. 10 . Measure the angle of incidence and the angle of reflection. 11 .Follow the above procedure and record your observation thrice.