Physics Questions and Answers
If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.
If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.
An electric pressing iron is connected to the mains using an insulated wire. wire becomes very hot.
The heat generated in the wire can be minimized by replacing the wire with one of?
thinner insulation.
greater diameter
smaller diameter
thicker insulation
Correct answer is B
No explanation has been provided for this answer.
Which of the arrangements of radiations below shows decreasing order of wavelengths?
X-rays> radio waves > infrared radiations
Radio waves> infrared radiations > X-rays
Infrared radiations > radio waves > X-rays
X-rays> infrared radiations > radio waves
Correct answer is B
radio waves have a longer wavelength than infrared light, and infrared than x-rays in the electromagnetic spectrum
Determine the speed of the wave.
64 cm/s
32 cm/s
24 cm/s
72 cm/s
Correct answer is D
Speed = Wavelength x Frequency
or
V = fλ, where frequency = 1/period, f = 1/T.
The period was given as 0.125sec and wavelength = 9cm
: f = 1/T = 1/0125 = 8.
V = fλ = 8 × 9 = 72m/s