The terms 'Event Horizon', 'Singularity', 'String Theory' and 'Standard Model' are sometimes seen in the news in the context of
- A.Observation and understanding of the Universe
- B.Study of the solar and the lunar eclipses
- C.Placing satellites in the orbit of the Earth
- D.Origin and evolution of living organisms on the Earth
Correct answer
Explanation
The correct answer is A, Observation and understanding of the Universe. All four terms come from physics and cosmology, the study of how the universe and its matter work.
An event horizon is the boundary around a black hole beyond which nothing, not even light, can escape. A singularity is the point at the centre of a black hole, or at the start of the Big Bang, where density becomes infinite and known laws break down. String theory proposes that the basic particles are tiny vibrating strings, in an attempt to unite gravity with quantum physics. The Standard Model describes the known elementary particles and three of the four fundamental forces; the Higgs boson found at CERN in 2012 completed it.
B is wrong because eclipses are explained by simple geometry of the Sun, Moon and Earth. C is wrong because placing satellites uses terms like orbital velocity and geostationary orbit. D is wrong because the origin of life is a subject of biology.
Exam tip: Event horizon and singularity belong to black holes; Standard Model to particles.
Practice Questions
View allWith reference to polyethylene terephthalate, the use of which is so widespread in our daily lives, consider the following statements :
1. Its fibres can be blended with wool and cotton fibres to reinforce their properties.
2. Containers made of it can be used to store any alcoholic beverage.
3. Bottles made of it can be recycled into other products.
4. Articles made of it can be easily disposed of by incineration without causing greenhouse gas emissions.
Which of the statements given above are correct?
- A.1 and 3
- B.2 and 4
- C.1 and 4
- D.2 and 3
Show answer
PET fibre (polyester) is blended with wool and cotton, and PET bottles are widely recycled into new products. Polyethylene terephthalate is a polyester made from ethylene glycol and terephthalic acid.
Read the full explanation →Consider the following pairs :
Objects in space : Description
1. Cepheids : Giant clouds of dust and gas in space
2. Nebulae : Stars which brighten and dim periodically
3. Pulsars : Neutron stars that are formed when massive stars run out of fuel and collapse
How many of the above pairs are correctly matched?
- A.Only one
- B.Only two
- C.All three
- D.None
Show answer
Only pair 3 is right; the descriptions of Cepheids and nebulae have been swapped. Cepheid variables are pulsating stars that brighten and dim on a regular cycle.
Read the full explanation →A charged particle moves through a magnetic field B with a velocity v. Which one of the following statements is true for the force (F) experienced by the particle?
- A.F is maximum when v and B are parallel to each other.
- B.F is maximum when v and B are anti-parallel to each other.
- C.F is maximum when v and B are perpendicular to each other.
- D.The force F is independent of the angle between v and B.
Show answer
The magnetic force depends on the sine of the angle between velocity and field, and sin 90° is the largest value.
Read the full explanation →In Sun-Earth system, the Sun, the Earth and the Lagrange point L4 form :
- A.an isosceles triangle
- B.an equilateral triangle
- C.a straight line
- D.a scalene triangle
Show answer
L4 lies on Earth's orbit 60° ahead of the Earth, so it is as far from the Sun as from the Earth.
Read the full explanation →Which one of the following is the most characteristic property of an element?
- A.Density
- B.Boiling point
- C.Mass number
- D.Atomic number
Show answer
The number of protons in the nucleus defines an element, and no two elements share it. The atomic number (Z) is the number of protons in an atom's nucleus, and in a neutral atom it also equals the number of electrons, which decide chemical behaviour.
Read the full explanation →