Delmars Unit 3

The precipitator uses a high-voltage DC power supply to provide a set of wires with a positive charge and a set of plates with a _____ charge.

negative

When an object protected by a lightning _____ is struck by a lightning bolt, it will bleed the lightning discharge to ground before the protected object can be harmed.

rod

A ____ charge can either be positive or negative

static

_____ means not moving

static

Electrostatic charges occur on _____.

insulators

Selenium changes it's conductivity with a change of

light intensity

the charge that accumulates on an object is determined by the ___ used to produce the charge

materials

The semiconductor material used as a coating on copy machine drums is _____.

Selenium

a lighting bolt has an average voltage of about

15,000,000 volts

_____ electricity is caused by an imbalance of electrical charges (positive and negative)

Static

A precipitator is a type of _____.

air filter

A lightning protection device that is grounded at one end, with the other end close to but not touching the object to be protected, is called a lightning _____

arrestor

Power lines are often protected by lightning _______________ that exhibit a very high resistance at the normal voltage of the line.

arrestors

Power lines are protected by lightning ____

arrestors

two types of protection from lightning strikes are

arrestors and insulators

when selenium is in the prescience of heavy light, it has high ____

conductivity

Nuisance static charges are more likely to occur when the air is _____.

dry

Insulators are the only materials that can hold _____ stationary.

electrons

an object can be positively charged by ____ from it

removing electrons

Selenium is a(n) _____.

semiconductor

The discharge of ___ in thunderclouds creates lightning bolts

static electricity

Before a electroscope can be used, it must first be _____

charged

A instrument that can be used to determine the polarity of the electrostatic charge of an object is a ____

electroscope

Within a lightning bolt, current flows _____.

from negative to positive

_____ is a semiconductor material that changes its conductivity with a change of light intensity

Selenium

an object can be negatively charged by ___ to it

adding