Thus, a metal used in storage batteries is Lead.

A flexible tube called an endoscope is used to view different parts of the digestive tract. When passed through the mouth (as shown on the left), an endoscope can be used to examine the esophagus, stomach, and some of the small intestine.

For short durations of time, sounds up to a 120 dB are bearable and also considered safe by the world health organization, but again, listening to sounds at such high frequencies at regular intervals of stretched time durations is totally unsafe and makes the ears vulnerable to permanent hearing loss.

In an AC circuit, magnetic reversal due to phase difference between current and voltage occurs 50 or 60 times per second. A capacitor helps to improve the power factor by relieving the supply line of the reactive power.