Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

Multiple choice physics life cycle of stars evolution and end stages of stars the stars stars

______________are the result of exploding stars that initially are more than about eight times the sun's mass.

  1. stars

  2. black hole

  3. supernova

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A supernova is the violent explosion of a massive star, typically one that is at least eight times the mass of the Sun, occurring at the end of its life cycle.

Multiple choice physics life cycle of stars evolution and end stages of stars the stars stars

Which of the following is the stage where a massive star explodes and releases a lot of energy?

  1. Red supergiant

  2. Blackhole

  3. Main sequence

  4. Supernova
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Stars with very large masses can become black holes. A black hole releases a huge amount of gravitational energy, as material swirls toward its event horizon. This energy produces a jet of particles that streams over a distance of 300,000 light-years.

Multiple choice physics life cycle of stars evolution and end stages of stars the stars stars

The constellation of stars appear at different positions in the sky at different times during night mainly ________________________.

  1. Because earth rotates about its axis

  2. Because Earth revolves round the sun

  3. Because of optical illusion

  4. Because celestial bodies are changing their positions all the time
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The apparent motion of stars and constellations across the sky during the night is primarily caused by the rotation of the Earth on its axis, which makes the celestial sphere appear to rotate in the opposite direction.

Multiple choice physics sound audible, infrasonic and ultrasonic sounds different sounds range of hearing

The sounds having frequency less than 20 Hz are called ultrasonics.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Human beings can normally hear sounds with a frequency between about 20 Hz and 20,000 Hz. Sounds with frequencies below 20 hertz are called infrasound. Infrasound is too low-pitched for humans to hear.

so the answer is B.

Multiple choice physics sound audible, infrasonic and ultrasonic sounds different sounds range of hearing

Which of the following frequencies of sound elephants produce ?

  1. ultrasonic

  2. infrasonic

  3. both A & B

  4. cant say
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Some of the elephant's vocalizations are infrasonic, and thus are inaudible to humans. The prominence of very low frequencies in the vocalizations is a defining characteristic of all three species of elephants. Sounds are generally considered to be infrasonic if their frequency is less than $20 Hz$ (the lower limit of human hearing). Low frequency sounds travel farther than high frequency ones, which make them ideal for long distance communication.
Hence, Elephants produce infrasonic sound. 

Multiple choice physics sound audible, infrasonic and ultrasonic sounds different sounds range of hearing

Name the sounds of the frequencies given below $10Hz$.

  1. $ultrasonic$
  2. $infrasonic$
  3. $supersonic$

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Infra-sound is a low-frequency sound. It is sound that is lower in frequency than $20 \ Hz$ or cycles per second, the normal limit of human hearing. Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high. The ear is the primary organ for sensing infra-sound, but at higher intensities it is possible to feel infra-sound vibrations in various parts of the body.

Multiple choice physics sound audible, infrasonic and ultrasonic sounds different sounds range of hearing

Infrasound can be heard by

  1. dog

  2. bat

  3. rhinoceros

  4. human beings
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Rhinos have extremely good ears, picking up infra-sound far deeper than the range of human hearing.
Rhinos, can hear down to a frequency of four hertz, whereas even a human baby, with entirely undamaged ears, can normally only pick up sounds as low as 20 hertz. Giraffes and elephants can also hear in this infra-sound range.