🔍 Key Concepts

• Relationship between peak value and instantaneous value of a sine wave at a given angle • Use of the sine function (sin θ) to find the instantaneous value from the peak value • Sign (positive or negative) of the sine function in different quadrants of the 0°–360° circle

💭 Think About

• How do you express the instantaneous voltage of a sine wave at an angle θ if you know the peak voltage? Write it as a simple formula. • What is sin(240°), and in which quadrant does 240° lie? How does that affect whether the result is positive or negative? • Which of the answer choices are close to the numerical value you get when you multiply the peak voltage by sin(240°)?

✅ Before You Answer

• Confirm that you are using peak value × sin(θ), not RMS or average values. • Verify whether 240° is in a quadrant where sine values are positive or negative. • Check that your calculator is in degrees, not radians, before finding sin(240°).