Intro to Physics Exam 2

When carbon and oxygen atoms combine, energy is

given off by the reaction

In an electrically neutral atom, the number of protons in the nucleus is balanced by an equal number of

Orbital Electrons

Which of the following are electrically neutral?

Neutron

How many different elements are in a water molecule?

two

The reason a granite block is mostly empty space is that the atoms in the granite are

mostly empty space themselves

Brownian motion has to do with the

Random motions of atoms and molecules

Nuclei of atoms that make up a newborn baby were made in

Ancient Stars

Which of the following is not a compound?

Air

What makes an element distinct?

Number of Protons

The smallest particle of those listed below is

Quark

Which of the following normally warms up fastest when heat is applied?

Iron

A substance that heats up relatively quickly has a

Low specific Heat

The moderate temperatures of islands throughout the world has much to do with water's

High Specific Heat

When you touch a cold piece of ice with your finger, energy flows

From your finger to the Ice

Ice tends to form first at the

Surface of Bodies of Water

The temperature at the bottom of Lake Tahoe, high in the Sierra Nevada Mountains in California, at this moment is

4 Degrees Celsius

Consider a sample of ice at 0 degrees C. If the temperature is decreased, the volume of the ice

Decreases

When a bimetallic bar made of copper and iron strips is heated, the bar bends toward the iron strip. The reason for this is

Copper expands more than iron

When water at 4 degrees C is heated it expands. When water at 4 degrees C is cooled, it

Expands

Which of the following expands when the temperature is lowered? Equal volumes of

Water at 4 Degrees C

If a volume of air is warmed, it expands. If a volume of air expands, it

Cools

Energy transfer by convection is primarily restricted to

Fluids

Objects that radiate relatively well

Absorb radiation relatively well

The higher the temperature of an object

the shorter the wavelengths it radiates

The planet Earth loses heat mainly by

Radiation

An object will normally be a net radiator of energy when its temperature is

Higher than its surroundings

Metals are both good heat conductors and good electrical conductors because of the

Looseness of outer electrons in metal atoms

Your feet feel warmer on a rug than on a tile floor because a rug

Is a better insulator than tile

Substances absorb heat energy by the process of

radiation, convection, conduction

A good heat conductor is

A poor insulator

Radio waves travel at the speed of light, 300,000 km/s. The wavelength of a radio wave received at 100 megahertz is

3.0 m

A node is a position of

minimum amplitude

If the frequency of a certain wave is 10 hertz, its period is

0.1 seconds

A common source of wave motion is a

Vibrating Object

A wiggle in time is a

Vibration

Which of the following is not a transverse wave?

Sound

How many vibrations per second are associated with a 101-MHz radio wave?

101,000,000

A standing wave occurs when

A wave reflects upon itself

In a longitudinal wave the compressions and rarefactions travel in

The same direction

The vibrations of a longitudinal wave move in a direction

Along the direction of wave travel

Compressions and rarefactions are characteristic of

Longitudinal Waves

Sound travels faster in

Steel

Reverberation is actually a case of

Re-echoed sound

When the speed of sound near the ground is greater than it is at higher altitudes, the sound tends to be bent

Upward

The approximate range of human hearing is

20-20,000 Hertz

The source of every sound is something that is

Vibrating

The speed of a sound wave in air depends on

The air temperature

Sound waves cannot travel in

A vacuum

A sound wave is a

longitudinal wave

Sound travels faster in air if the air temperature is

Warm

The electrical force between charges is strongest when the charges are

Close Together

When the distance between two charges is halved, the electrical force between the charges

Quadruples

In an electrically neutral atom the number of protons in the nucleus is equal to the number of

Electrons that surround the nucleus

To say that electric charge is conserved is to say that electric charge

Can be neither created nor destroyed

The fundamental force underlying all chemical reactions is

Electrical

Strip electrons from an atom and the atom becomes a

Positive Ion

The electrical force between charges depends only on the charges'

Magnitude and separation distance

To say that an object is electrically polarized is to say

Its charges have been rearranged

A main difference between gravitational and electric forces is that electrical forces

Repel or attract

A balloon will stick to a wooden wall if the balloon is charged

Either positively or negatively

Like kinds of magnetic poles repel while unlike kinds of magnetic poles

Attract

An electron is shot through a spot somewhere between the ends of a horseshoe magnet. The electron

Direction is changed

The force on an electron moving in a magnetic field will be the largest when its direction is

Perpendicular to the magnetic field direction

The source of all magnetism is

Moving electric charge

Magnetism is due to the motion of electrons as they

Move around the nucleus and spin on their axes

If a steady magnetic field exerts a force on a moving charge, that force is directed

At right angles to the direction of the motion

Magnetic field lines about a current-carrying wire

Circle the wire in closed loops

An iron rod becomes magnetic when

The net spins of its electrons are in the same direction

Which force field can increase a moving electron's speed?

An electric field

Compared to the huge force that attracts an iron tack to a strong magnet, the force that the tack exerts on the magnet is

Equally huge

Rapid change of a magnetic field induces

an electric field

The output power of an ideal transformer is

Equal to the input power

When there is a change in the magnetic field in a closed loop of wire

a current is created in the loop of wire, a voltage is induced in the wire, electromagnetic induction occurs

When a bar magnet is thrust into a coil of copper wire, the coil tends to

Repel the magnet as it enters

Compared to the primary voltage, the secondary voltage may be

Larger, smaller, or the same

An electric motor is very similar to

An electric generator

Thrust a magnet into a coil of wire and the coil

Becomes an electromagnet, and has a current in it

If a magnet is pushed into a coil, voltage is induced across the coil. If the same magnet is pushed into a coil with twice the number of loops

Twice as much voltage is induced

Power is transmitted at high voltages because the corresponding current in the wires is

Low so that overheating of the wires is minimized

A device that transforms electrical energy to mechanical energy is a

motor

Electromagnetic induction occurs in a coil when there is a change in

Magnetic field intensity in the coil

A transformer actually transforms

Voltage

Voltage can be induced in a wire by

 

changing the current in a nearby wire, moving the wire near a magnet, and moving a magnet near the wire.

A step-up transformer increases

Neither power nor energy

The metal detectors that people walk through at airports operate via

Faraday’s law