A jet aircraft engine emits a sound of frequency \(1.4 kHz\).
If the jet is travelling towards a stationary observer at \(240ms^{-1}\), calculate the frequency of the sound detected by the observer (speed of sound \(=340ms^{-1}\)).
\[0.821 kHz\]
\[3.36 kHz\]
\[4.76 kHz\]
A man standing at the side of the road hears the siren of an approaching fire engine. He hears a frequency of \(1.34 kHz\) (speed of sound \(=340ms^{-1}\)).
The siren on the fire engine has a frequency of \(1300Hz\). Calculate the speed of the fire engine.
\[10.1ms^{-1}\]
\[-10.5ms^{-1}\]
\[34.0ms^{-1}\]
The siren on the fire engine has a frequency of \(1300Hz\). What frequency of sound would be heard as the fire engine moves away?
\[1260 Hz\]
\[1300Hz\]
\[1340 Hz\]
A distant star is travelling directly away from the Earth at a speed of \(2.3 \times 10^{7}ms^{-1}\).
Calculate the value of \(z\) for this star.
(Speed of light \(c=3 \times 10^{8}ms^{-1}\))
(Hubble's constant \(H_{0}=2.3 \times 10^{-18}s^{-1}\))
\[0.0767\]
\[0.0767ms^{-1}\]
\[13.0\]
A hydrogen line in the spectrum of light from this star is measured to be \(443 nm\).
Calculate the wavelength of this line when it is observed from a stationary hydrogen source on Earth.
\[409 nm\]
\[443 nm\]
\[477nm\]
An astronomer estimates the speed that a star is moving from the Earth to be \(1.9 \times 10^{8}ms^{-1}\).
Calculate the approximate distance, in metres of the star from the Earth.
\[8.26 \times 10^{25}m\]
\[8.26 \times 10^{- 11}m\]
\[1.30 \times 10^{26}m\]
What is the main evidence for dark energy?
Signals from space probes entering a black hole
The observation of rotational speed of stars in our galaxy
Cosmic microwave background radiation
Which of the curves in the diagram originates from the hottest star?
Curve A
Curve B
Curve C
What radiation is evidence for the big bang?
Stellar radio incident radiation
Deep space infrared ambient radiation
Cosmic Microwave Background radiation (CMB)