# Some math questions I need checked

• indiansfan4life
In summary: E=I/d^2 E= 78/4.6^2 = 3.6In summary, the conversation covers various problems related to light and optics, such as the wavelength of a wave, the index of refraction, luminous flux, illuminance, and angles of refraction and incidence. The answers provided are 100.4 x 10^6 for #15, 1.22 for #16, 24.44 degrees for #19, 40.37 degrees for #20, and 3.6 for #22. However, the person asking for help is unsure and has shown their attempts at solving the problems.
indiansfan4life
analysis:
10. the picture that we see in a mirror is called the
11. the actual object that makes a picture that we see on a mirror is called the

15. What is the wavelength of a wave with a frequency of 100.4 MHz?

16. A substance allows light to travel through it with a velocity of 2.45 x10^8 m/s. What is the substances index of refraction?

17. What is the intensity of a light that has a lumnious flux of 750 lumens?

18. What is the illuminance provided by a light with a luminous flux of 1120 lm when it is 2.3 meters away?

19. What would the angle of refraction be if a light ray starts in a diamond and goes into the air it has an angle of incidence of 9 degrees.

20. What is the critical angle of light going from quartz to air?

22. What is the illuminance of a light when it is 4.6 m away from a light with an intensity of 78 candle power?

thanks for any help I don't know what I am doing

#15: .335 m
#16: 1.22
#17: I was not sure how to do this one.
#18: I was also not sure how to do this one.
#19: 24.44 degrees
#20: 40.37 degrees
#22. 3.6

Show that you've tried. Providing the answers is not enough.

#15: 100.4 x 10^6

3 x 10^8

divide c by f

=.335

#16: 2.45 x 10^8/ 3x 10^8 =1.22
#17: Like I said, I don't know what to do
#18: Dunno what to do
#19: 2.417(SIN)Q2=1(SIN)90
=24.44 degrees
#20: I just plugged it in and got 40.37 degrees for this one
SIN X= 1/1.544 then I did some other work to get the angle

#22: I wasn't really sure with this one but I used the illuminance equation to solve. I doubt it's right.

## 1. What is the difference between a factor and a multiple?

A factor is a number that divides evenly into another number, while a multiple is a number that is the result of multiplying a given number by another number. For example, 3 is a factor of 6 because it can divide into 6 evenly, and 12 is a multiple of 3 because it is the result of multiplying 3 by 4.

## 2. How do I find the perimeter of a rectangle?

The perimeter of a rectangle is found by adding together all four sides of the rectangle. If the length and width are labeled as l and w, the formula for perimeter is 2(l+w).

## 3. What is the difference between an acute angle and an obtuse angle?

An acute angle is an angle that measures less than 90 degrees, while an obtuse angle is an angle that measures greater than 90 degrees but less than 180 degrees.

## 4. What is the order of operations in math?

The order of operations in math is the sequence in which mathematical operations should be carried out in an expression. The acronym "PEMDAS" is often used to remember the order: Parentheses, Exponents, Multiplication and Division (from left to right), and Addition and Subtraction (from left to right).

## 5. How do I convert a decimal to a fraction?

To convert a decimal to a fraction, first write down the decimal as a fraction with the decimal value as the numerator and 1 as the denominator. Then, multiply the fraction by a power of 10 to eliminate the decimal. Finally, simplify the resulting fraction if possible.

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