Unit 5 Science Test

Question 1

When a nail wrapped in wire is used as a bar magnet, what must occur to enable a current to run through the circuit?

Answer 1

The circuit needs to be closed.

Question 2

When using a wire wrapped nail as a bar magnet in a circuit, what will most likely be produced around the nail when a current runs through the circuit runs through the circuit?

Answer 2

A magnetic field is produced.

Question 3

When you use a wire wrapped nail as a bar magnet in a circuit what is created?

Answer 3

An electromagnet

Question 4

What are electromagnets used for?

Answer 4

found in a junkyard attached to a crane to pick up cars and other metal objects

Question 5

According to electromagnetic induction, what will be created if a bar magnet is moved quickly back and forth in a coil of copper wire?

Answer 5

An electric current

Question 6

True or False?
An electric current always produces a magnetic field.

Answer 6

True

Question 7

How does a compass work?

Answer 7

A compass points toward magnetic north.

Question 8

What is the North Pole attracted to?

Answer 8

the South Pole.

Question 9

A generator converts _________ energy to _______________ energy by using a conducting metal loop turning in a magnetic field.

Answer 9

mechanical
electrical

Question 10

Draw an electromagnet and label its three parts

Answer 10

iron nail, coiled wire, and battery

Question 11

What are three things that increase the strength of an electromagnet?

Answer 11

-Increase loops in wire around nail
-increase current in wire by increasing battery power
-stronger/better iron core nail materials

Question 12

What are two things that use electromagnets?

Answer 12

-door safety magnets
-junkyard magnets

Question 13

True or False?
Conductors are materials like wood and plastic that hold onto their electrons?

Answer 13

False - wood and plastic are examples of insulators

Question 14

What is an example of friction?

Answer 14

rubbing a balloon in your hair

Question 15

What is an example of conduction?

Answer 15

touching a metal sphere that has been charged by a Van de Graff generator.

Question 16

What is an example of induction

Answer 16

being struck by lightning because you are standing near a tree.

Question 17

What are the two factors that influence gravitational force?

Answer 17

-mass of an object
-distance from object

Question 18

Explain how gravitational force can be strengthened and how it can be reduced using the words mass and distance.

Answer 18

It can be strengthened with a high mass and a close distance.
It can be reduced with a low mass and a far distance.

Question 19

True or False?
Mass changes due to gravity.

Answer 19

False - weight changes due to gravity

Question 20

True or False?
In a controlled vacuum chamber, a bowling ball and a pack of feathers dropped from the same height will land at the same time.

Answer 20

True - Acceleration of gravity is 9.8 m/s2 on Earth