Proportionality and Its Applications

The video tutorial covers the concepts of direct and inverse proportionality, explaining how variables can be constant multiples of each other. It provides examples of direct proportionality, such as y = 3x, and inverse proportionality, like y = 5(1/x). The tutorial also solves problems involving these concepts, including applications in Ohm's Law and light intensity, demonstrating how to find proportionality constants and solve for unknowns.

What does it mean when two variables are directly proportional?

• They are constant multiples of each other.

• They are equal to each other.

• They have no relationship.

• They are inversely related.

If y is directly proportional to x, which of the following is true?

• y = k/x

• y = kx

• y = x/k

• y = x + k

What is the relationship between y and x if y = 5 * (1/x)?

• y is directly proportional to x.

• y is equal to x.

• y is unrelated to x.

• y is inversely proportional to x.

In the equation a = 10/b, what is the relationship between a and b?

• a is equal to b.

• a is inversely proportional to b.

• a is unrelated to b.

• a is directly proportional to b.

If x is proportional to y and inversely proportional to z, which equation represents this relationship?

• x = k * z / y

• x = k * y * z

• x = k / (y * z)

• x = k * y / z

What is the value of k1 if x = 2 when y = 10 and x is directly proportional to y?

• 2

• 1/5

• 1/2

• 5

According to Ohm's Law, how is current related to resistance?

• Unrelated

• Directly proportional

• Inversely proportional

• Equal

If the current is 2.5 amperes when the resistance is 20 ohms, what is the constant of proportionality?

• 50

• 100

• 75

• 25

What does the inverse square law of light intensity state?

• Intensity is directly proportional to distance.

• Intensity is inversely proportional to distance.

• Intensity is inversely proportional to the square of the distance.

• Intensity is equal to the distance.

If a light meter registers 35 lux at 10 meters, what is the intensity at 25 meters?

• 5.6 lux

• 10 lux

• 15 lux

• 20 lux