At a point A, 20 metres above the level of water in a lake, the

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsShort Answer Type

171.

A man standing on the deck of a ship, which is 10 m above water level, observes the angle of elevation of the top of a hill as 60° and the angle of depression of the base of a hill as 30°. Find the distance of the hill from the ship and the height of the hill.

3152 Views

172.

The angle of elevation of the top Q of a vertical tower PQ from a point X on the ground is 60o. From a point Y, 40 m vertically above X, the angle of elevation of the top Q of the tower is 45o. Find the height of the tower PQ and the distance PX. Use square root of 3 space equals 1.73

4614 Views

173.

In Given figure, a tower AB is 20 m high and BC, its shadow on the ground, is m20 square root of 3 long. Find the sun's altitude.

2000 Views

174. The angle of elevation of an aeroplane from a point A on the ground 60°. After a flight of 15 seconds, the angle of elevation changes to 30°. If the aeroplane is flying at a constant height of 1500 space square root of 3 space end root space straight m, find the speed of the plane in km/hr.

1213 Views

Advertisement

 Multiple Choice QuestionsLong Answer Type

Advertisement

175. At a point A, 20 metres above the level of water in a lake, the angle of elevation of a cloud is 30°. The angle of depression of the reflection of the cloud in the lake, at A is 60°. Find the distance of the cloud from A.



Let BE be the surface of the lake. Suppose C be the position of the cloud and C' be its reflection in the lake.
Then, AB = 20 m

Let CD = x m. Then,

CE =C'E = ( x + 20)

In ΔACD,

tan space 30 degree space equals space CD over AD
rightwards double arrow space fraction numerator 1 over denominator square root of 3 space end fraction space equals space straight x over AD

rightwards double arrow AD space equals space straight x square root of 3 space space.. space left parenthesis straight i right parenthesis

Also comma

sin space 30 degree space equals space CD over AC

rightwards double arrow space 1 half space equals space straight x over AC
rightwards double arrow space AC space equals 2 straight x space.... space left parenthesis ii right parenthesis

Now comma space in space ΔADC apostrophe comma
tan space 60 degree space equals space fraction numerator straight C apostrophe straight D over denominator AD end fraction
rightwards double arrow space square root of 3 space equals space fraction numerator left parenthesis straight x space plus 20 right parenthesis space plus space 20 over denominator AD end fraction
rightwards double arrow space AD space equals space fraction numerator left parenthesis straight x space plus 40 right parenthesis over denominator square root of 3 end fraction space... space left parenthesis iii right parenthesis
From space left parenthesis straight i right parenthesis space and space left parenthesis iii right parenthesis comma space we space get
straight x square root of 3 space equals space fraction numerator left parenthesis straight x space plus space 40 right parenthesis over denominator square root of 3 end fraction
rightwards double arrow space 3 straight x space equals space straight x space plus 40
rightwards double arrow space 2 straight x space equals space 40
rightwards double arrow space straight x space equals space 20
2179 Views

Advertisement

 Multiple Choice QuestionsShort Answer Type

176.

The ratio of the height of a tower and the length of its shadow on the ground is √3:1. What is the angle of elevation of the sun?

18184 Views

177.

A moving boat is observed from the top of a 150 m high cliff moving away from the cliff. The angle of depression of the boat changes from 60° to 45° in 2 minutes. Find the speed of the boat in m/h.

7636 Views

 Multiple Choice QuestionsLong Answer Type

178.

The angle of elevation of a cloud from a point 60 m above the surface of the water of a lake is 30° and the angle of depression of its shadow in water of lake is 60°. Find the height of the cloud from the surface of the water. 

4138 Views

Advertisement

 Multiple Choice QuestionsShort Answer Type

179.

As observed from the top of a 100 m high light house from the sea-level, the angles of depression of two ships are 30° and 45°. If one ship is exactly behind the other on the same side of the light house, find the distance between the two ships. [ Use √3= 1.732 ]


 Multiple Choice QuestionsMultiple Choice Questions

180.

The angle of depression of a car, standing on the ground, from the top of a 75 m high tower, is 30o. The distance of the car from the base of the tower (in m.) is

  • 25√3

  • 50√3

  • 75√3

  • 150


Advertisement