upsc general study 10years pape

GS Paper 1

By Year
By Subject

UPSC Previous Year Solved Papers
SCIENCE & TECH

1. Satellites used for telecommunication relay are kept in a geostationary orbit. A satellite is said to be in such as orbit when:

The orbit is geosynchronous.
The orbit is circular.
The orbit lies in the plane of the earth's equator.
The orbit is at an altitude of 22,236.

Select the correct answer using the codes given below:

1, 2 and 3 only

1, 3 and 4 only

2 and 4 only

1, 2, 3 and 4

Explanation: A. A geostationary orbit (or Geostationary Earth Orbit - GEO) is a geosynchronous orbit directly above the Earth's equator (0

2. An artificial satellite orbiting around the Earth does not fall down. This is so because the attraction of Earth

does not exist at such distance

is neutralized by the attraction of the moon

provides the necessary speed for its steady motion

provides the necessary acceleration for its motion

Explanation: D. An artificial satellite moving round the Earth in a circular orbit possesses an acceleration which is "constant" in magnitude but "changing in direction". An artificial satellite revolves round the earth under Centripetal Acceleration. By the launch rocket, immediately before the satellite is established in the predetermined orbit, the speed given to it is 30, 000 km/hr. The speed must be great enough so gravity doesn

3. What is the difference between Blue-tooth and Wi-Fi devices?

Bluetooth uses 2.4 GHz radio frequency band, whereas Wi-Fi can use 2.4 GHz or 5 GHz frequency band

Bluetooth is used for Wireless Local Area Networks (WLAN) only, whereas Wi-Fi is used for wireless wide area networks (WWAN) only

When information is transmitted between two devices using Bluetooth technology, the devices have to be in the line of sight of each other, but when Wi-Fi technology is used the devices need not be in the line of sight of each other

The statements (A) and (B) given above are correct in this context

Explanation: A. Bluetooth networking transmits data via low power radio waves. It communicates on a frequency of 2.45 gigahertz (actually between 2.402 GHz and 2.480 GHz, to be exact). Wi-Fi -IEEE 802.11 is a set of standards for implementing wireless local area network (WLAN) computer communication in the 2.4, 3.6 and 5 GHz frequency bands.

4. What is the difference between a CFL and an LED lamp?

To produce light, a CFL uses mercury vapour and phosphor while an LED lamp uses semiconductor material
The average life span of a CFL is much longer than that of an LED lamp
A CFL is less energy-efficient as compared to an LED lamp

Which of the statements given above is/are correct?

1 only

2 and 3 only

1 and 3 only

1, 2 and 3

Explanation: C. LED bulbs are grouped in clusters with diffuser lenses which have broadened the applications for LED use in the home.

5. A new optical disc format known as the Blu-ray Disc (BD) is becoming popular. In what way is it different from the traditional DVD?

DVD supports Standard Definition video while BD supports high definition video
Compared to a DVD, the BD format has several times more storage capacity
Thickness of BD is 2.4 mm while that of DVD is 1.2 mm.

Which of the statements given above is/are correct?

1 only

1 and 2 only

2 and 3 only

1,2 and 3

Explanation: B. Statement 3 is incorrect as the thickness of BD is1.1 mm while that of DVD is 1.2 mm. The difference lies in capacity so statement 2 is correct. As far as statement 1 is concerned.

6. What is "Virtual Private Network"?

It is a private computer network of an organization where the remote users can transmit encrypted information through the server of the organization.

It is a computer network across a public internet that provides users access to their organization

It is a computer network in which users can access a shared pool of computing resources through a service provider.

None of the statements (A), (B) and (C) given above is correct description of Virtual Private Network.

Explanation: A. Virtual Private Network is a method of computer networking typically using the public internet that allows users privately share information between remote locations, or between a remote location and a business home network.