***Write 5 Synonyms and an antonym for the following words***
Rewrite the following sentences using and, but, or, nor, for, so, yet
Fill in the blanks using proper words or phrases.
Paraphrase the following sentences. Try to change words, phrases and sentence structures wherever you can. There are more than one way of forming these sentences.
Write the write words from the BELOW passage in the blanks to answer the following questions (21-25)
An astronomical object which has its mass so densely packed that even light cannot escape its surface can be defined as a Black Hole. In other words, the objects that are not visible to us as the light emitted or reflected by them cannot escape its own surface are called Black Holes.
But if the light does not escape from Black Holes and we cannot see them, how do we know about them. We actually cannot see black holes directly but astronomers observe them indirectly through the behaviour of the surrounding objects such as objects and other material being sucked into the black hole and stars revolving around massive darkness.
To understand the concept of Black Holes we must also understand the concept of Escape Velocity. Escape velocity is the speed an object is required to attain to beat the gravitational attraction of another body from which it is trying to move away. For example, a rocket must accelerate to 11.2 km/s in order to escape Earth's gravity and this velocity is termed as escape velocity of the earth. Escape Velocity depends mainly on two factors; firstly, the mass of body whose gravitation force must be superseded and secondly the distance between the centre of the object and the object trying to move away by escaping its gravitational pull. This suggests that more the mass of the body, then the escape velocity shall be higher and similarly it is also higher if the distance between the centre of an object is lesser.
Further, it suggests that every object of certain mass will have its escape velocity equal to the speed of light at a certain radius of that object. This radius of an object, where its escape velocity is equal the speed of light is called Schwarzschild radius. It means that if any object has its radius lesser than its Schwarzschild radius then even light cannot escape its gravitational force and such objects are called Black Holes. For instance, if the radius of Sun which is around 6.95 lakh kilometres is reduced to a little less than 3 kilometres, then Sun would turn into a Black Hole.
Read the passage above and state if the following statements (26-30) are True, False or Not-Given.
26. Black Holes are denser than normal astronomical bodies in the space
27. Astronomers can directly see the Black Holes.
28. A rocket has to maintain same escape velocity even after it gains altitude of around 1000 km above the Earth.
29. The Schwarzschild radius of the stars we see in space is lesser than their physical radius.
30. The radius of the Schwarzschild radius of the Sun is little less than 3 kilometres.
Listen to the audio from BBC Learning English and Answer the following questions (32-40) with no more than three words.
Play the audio and answer below questions