Hearing aid

A hearing aid is an electro acoustic body-worn apparatus which typically fits in or behind the wearer’s ear, and is designed to amplify and modulate sounds for the wearer.

It makes some sounds louder so that a person with hearing loss can listen, communicate, and participate more fully in daily activities. A hearing aid can help people hear more in both quiet and noisy situations. However, only about one out of five people who would benefit from a hearing aid actually uses one.The hearing aid receives sound through a microphone, which converts the sound waves to electrical signals and sends them to an amplifier. The amplifier increases the power of the signals and then sends them to the ear through a speaker.

The Respiratory System is Designed to Bring in Oxygen and Remove Carbon Dioxide

• A person with an average ventilation rate of 7.5 L/min will breathe in and out 10,800 liters of gas each day
• From this gas the person will take in about 420 liters of oxygen (19 moles/day) and will give out about 340 liters of carbon dioxide (15 moles/day)
• The ratio of CO2 expired/O2 inspired is called the respiratory quotient (RQ)
  • RQ = CO2 out/O2 in = 340/420 = 0.81
  • In cellular respiration of glucose CO2 out = O2 in; RQ = 1

Phototherapy

Definition

Phototherapy, or light therapy, is the administration of doses of bright light in order to normalize the body‘s internal clock and/or relieve depression.

DESCRIPTION

Phototherapy is generally administered at home. The most commonly used phototherapy equipment is a portable lighting device known as a light box. The box may be mounted upright to a wall, or slanted downwards towards a table. The patient sits in front of the box for a prescribed period of time (anywhere from 15 minutes to several hours).

Both Light and Sound Have Oscillating Waves

• Sound and light are waves in which the amplitude oscillates with time
  • For pure tones or colors the oscillation is a sine wave with a fixed wavelength and frequency
  • The wavelength is the distance between 2 peaks of the wave

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WHAT IS TONOMETER?

THIS PARAGRAPH HAS BEEN WRITTEN IN REFERENCE TO MDU ROHTAK EXAM PATTERN

In order to ensure a person’s optic nerves are healthy, optometrists check the pressure placed on them by the fluid in the eyes. This pressure is called intraocular pressure and should measure between 10 mmHg and 21 mmHg. Measurements that are higher than normal can be a sign of early glaucoma or retinal detachment.