Photo AI
Read the following passage and answer the accompanying questions - Leaving Cert Physics - Question 11 - 2018
Question 11
Read the following passage and answer the accompanying questions. The Irish Low Frequency Array, or I-LOFAR, is part of a €150 million network of radio telescope st... show full transcript
Worked Solution & Example Answer:Read the following passage and answer the accompanying questions - Leaving Cert Physics - Question 11 - 2018
Step 1
Calculate the minimum frequency of the radio waves detected by I-LOFAR.
Answer
To find the minimum frequency ( f) we can use the formula: Given that the wavelength ( \lambda) is 30 m, and assuming the speed of light (v) is approximately , we calculate: f = \frac{3 \times 10^8 m/s}{30 m} = 1 \times 10^7 Hz.
Step 2
Draw a diagram of the magnetic field around the Earth.
Answer
Draw a simple sketch showing the Earth with a series of field lines extending outward and around it. The lines should resemble concentric circles around the Earth, indicating the direction of the magnetic field lines pointing from the north pole to the south pole.
Step 3
Explain how information is transmitted using optical fibres.
Answer
Information is transmitted through optical fibres by using light. When light travels through the glass core of the fibre, it reflects internally due to the principle of total internal reflection. The light carries information in the form of signals, allowing for high-speed data transmission. The angle of incidence of the light must be greater than the critical angle for the internal reflection to occur.
Step 4
Calculate the position of the image of a person standing 75 cm from the Leviathan mirror.
Answer
Using the mirror formula: Given that u = -75 cm (object distance) and f = -16 m (focal length converted to cm: -1600 cm), we rearrange the formula to find v: Thus: Calculating gives ( v \approx 79 cm ), indicating the position is 79 cm behind the mirror.
Step 5
Where, with respect to the concave mirror, will an image of the moon be formed? Justify your answer.
Answer
The image of the moon will be formed at the focal point of the mirror, because the rays of light coming from the moon are parallel when they reach the mirror, and they converge at the focal point due to the properties of concave mirrors.
Step 6
A concave mirror can also be used as a microscope to magnify images. Draw a ray diagram to show the formation of an upright, magnified image in a concave mirror.
Answer
Draw a diagram showing an object placed between the focal point and the mirror. Indicate the object, mirror, and the rays of light reflecting from the mirror. The reflected rays should diverge, forming an upright image on the same side as the object.
Step 7
Calculate the velocity of the Hubble telescope as it orbits the Earth.
Answer
The velocity (v) can be calculated using the formula: v = \frac{2\pi r}{T} Given that the radius (r) is 6400 km (converted to meters = 6400000 m) and T = 7650 s (orbital period), we find: v = \frac{2\pi(6400000)}{7650} \approx 7650 m/s.
Step 8
Name one optical phenomenon which reduced the effectiveness of the Leviathan and which is eliminated by the location of the Hubble telescope. How does the location of the Hubble telescope eliminate this problem?
Answer
One optical phenomenon that reduced the effectiveness of the Leviathan was 'atmospheric refraction'. The Hubble telescope's location in space eliminates this issue, allowing it to take clearer images free from atmospheric distortion.