31: Which one of the following is NOT an astronomical object?
(a) Pulsar
(b) Brittle Star
(c) Black hole
(d) Quasar
32: The surface of a lake is frozen in severe winter, but the water at its bottom is still liquid. What is the reason?
(a) Ice is a bad conductor of heat
(b) Since the surface of the lake is at the same temperature as the air, no heat is lost
(c) The density of water is maximum at 4 degree celcius
(d) None of the statements (a), (b) and (c) given above is correct.
Explanation:
In cold winter months, lakes and rivers freeze over forming ice. All liquids expand on heating, but water is an exception to this rule. If water is heated, its volume gradually decreases. (This decrease in volume continues till the temperature rises to 4 degree C.) At temperatures over 4 degree C water starts expanding. It then keeps expanding with the further rise in temperature, till finally at 100 degree C it turns into steam. At 4 degree C, water has the least volume (occupies the least amount of space) and maximum density (is at its heaviest). This irregular expansion of water is called anomalous expansion.
During winter months in colder countries the outside or atmospheric temperature is very low - it drops to below freezing - and the upper layers of water in the lakes and ponds start cooling. When the temperature of the surface layers falls to 4 degree C, the water body acquires maximum density and sinks down. The water that sinks down displaces water below, and the lower layers of water simultaneously rise up. This also gets cooled to 4 degree C and again sinks down.
When the temperature of the water body finally goes below 4 degree C, the density or heaviness of water decreases and as a result water does not sink down. The surface water finally freezes at 0 degree C while the lower part still remains at 4 degree C. The light frozen layer of ice floats on top.
33: Consider the following statements:
1. The repo rate is the rate at which other banks borrow from the Reserve Bank of India.
2. A value of 1 or Gini Coefficient in a country inplies that there is perfectly equal income for everyone in its population.
Which of the statements given above is/are correct ?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Explanation:
Repo rate is the rate at which the RBI borrows from the banks, while the bank rate is the rate at which the banks borrow from the RBI.
34: Consider the following in respect of 'National Career Service':
1. National Career Service is an initiative of the Department of Personnel and Training, Government of India.
2. National Career Service has been launched in a Mission Mode to improve the employment opportunities to uneducated youth of the country.
Which of the above statements is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
35: At what temperature are the readings of a Centigrade and Fahrenheit thermometer the same?
(a) -40
(b) 212
(c) 40
(d) 100