### All High School Physics Resources

## Example Questions

### Example Question #3 : Waves

After exercising, Jane takes her pulse. She realizes that her heart is beating rapidly, approximate four beats every second. What is the period of her elevated heart rate?

**Possible Answers:**

**Correct answer:**

When you see a relationship like "times every second" or "once per hour," these are hints you are looking at a frequency. Frequency is, effectively, how often something happens. If it happens four times per second, then we know how often it happens. The units "per second" are equivalent to Hertz.

The relationship between frequency and period is .

Since our given frequency was four beats per second, or , we can solve for the period.

This means that her heart beats once every 0.25 seconds.

### Example Question #4 : Waves

A radio station broadcasts at a frequency of . If the broadcast is an electromagnetic wave, then what is its wavelength?

**Possible Answers:**

**Correct answer:**

The relationship between wavelength and frequency is given by the equation , where is the wavelength, is the speed of light, and is frequency.

We are given the values for frequency and the speed of light, allowing us to solve for the wavelength.

### Example Question #5 : Waves

A wave oscillates with a speed of and has a wavelength of . What is the frequency of the wave?

**Possible Answers:**

**Correct answer:**

The equation for velocity in terms of wavelength and frequency is .

We are given the velocity and the wavelength. Using these values, we can solve for the frequency.

### Example Question #6 : Waves

A symphony tunes to an oboe playing a note at . If the speed of sound is , what is the wavelength of this note?

**Possible Answers:**

**Correct answer:**

The relationship between velocity, frequency, and wavelength is:

Plug in the given information to solve:

### Example Question #7 : Waves

A note is played with a wavelength of . If the speed of sound is , what is the frequency of the note?

**Possible Answers:**

**Correct answer:**

The relationship between velocity, frequency, and wavelength is:

Plug in the given information to solve:

### Example Question #8 : Waves

A wave has a frequency of . What is its period?

**Possible Answers:**

**Correct answer:**

The relationship between frequency and period is .

Plug in our given value:

### Example Question #9 : Waves

A wave with a constant velocity doubles its frequency. What happens to its wavelength?

**Possible Answers:**

The wavelengths will be the same.

The new wavelength will also double.

There is insufficient information to solve.

The new wavelength will be the old wavelength.

**Correct answer:**

The new wavelength will be the old wavelength.

The relationship between velocity, frequency, and wavelength is:

In this case we're given a scenario where and . The velocities equal each other because the problem states it has a constant velocity. Therefore we can set these equations equal to each other:

Notice that the 's cancel out:

Divide both sides by two:

### Example Question #1 : Understanding Wavelength And Frequency

A drummer beats his drum every . What is the frequency of the drum beat?

**Possible Answers:**

**Correct answer:**

Period describes the amount of time per event cycle. The relationship between period and frequency is .

We are given the period, allowing us to solve for the frequency.

### Example Question #2 : Understanding Wavelength And Frequency

A microwave has a wavelength of . What is the frequency of the wave?

**Possible Answers:**

**Correct answer:**

The velocity of a wave is equal to the product of the wavelength and frequency:

We can rearrange this formula to solve for the frequency.

Since microwaves are on the electromagnetic spectrum, their velocity will be equal to the speed of light. We are given the wavelength. Using these values, we are able to solve for the frequency.

### Example Question #3 : Understanding Wavelength And Frequency

A certain type of radiation on the electromagnetic spectrum has a frequency of . What is the wavelength of this radiation?

**Possible Answers:**

**Correct answer:**

The velocity of a wave is equal to the product of the wavelength and frequency:

We can rearrange this formula to solve for the wavelength.

We can use the given values for the frequency and velocity to solve for the wavelength.

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