58687.If the length of the shadow of a tree is decreasing then the angle of elevation is:
Increasing
Decreasing
Remains the same
None of the above
Explanation:
See the following figure:
As the shadow reaches from point D to C towards the direction of the tree, the angle of elevation increases from 30° to 60°.
58688.The angle of elevation of the top of a building from a point on the ground, which is 30 m away from the foot of the building, is 30°. The height of the building is:
10 m
$\dfrac{30}{\sqrt{3}}$ m
$\dfrac{\sqrt{3}}{10}$ m
30 m
Explanation:
Say x is the height of the building.
a is a point 30 m away from the foot of the building.
Here, height is the perpendicular and distance between point a and foot of building is the base.
The angle of elevation formed is 30°.
Hence, tan 30° = $\dfrac{perpendicular}{base}$ = $\dfrac{x}{30}$
$\dfrac{1}{\sqrt{3}}$ = $\dfrac{x}{30}$
x =$ \dfrac{30}{\sqrt{3}}$
58689.If the height of the building and distance from the building foot’s to a point is increased by 20%, then the angle of elevation on the top of the building:
Increases
Decreases
Do not change
None of the above
Explanation:
We know, for an angle of elevation θ,
tan θ = $\dfrac{Height of building}{Distance from the point}$
If we increase both the value of the angle of elevation remains unchanged.
58690.If a tower 6m high casts a shadow of $2\sqrt{3}$ m long on the ground, then the sun’s elevation is:
60°
45°
30°
90°
Explanation:
As per the given question:
Hence,
tan θ = $\dfrac{6}{2\sqrt{3}}$
tan θ = $\sqrt{3}$
tan θ = tan 60°
⇒ θ = 60°
58691.The angle formed by the line of sight with the horizontal when the point is below the horizontal level is called:
Angle of elevation
Angle of depression
No such angle is formed
None of the above
Explanation:
The angle formed by the line of sight with the horizontal when the point is below the horizontal level is called angle of depression.
58692.The angle formed by the line of sight with the horizontal when the point being viewed is above the horizontal level is called:
Angle of elevation
Angle of depression
No such angle is formed
None of the above
Explanation:
The angle formed by the line of sight with the horizontal when the point being viewed is above the horizontal level is called angle of elevation.
58693.From a point on the ground, which is 15 m away from the foot of the tower, the angle of elevation of the top of the tower is found to be 60°. The height of the tower (in m) standing straight is:
15$\sqrt{3}$
10$\sqrt{3}$
12$\sqrt{3}$
20$\sqrt{3}$
Explanation:
We know:
tan (angle of elevation) = height of tower/its distance from the point
tan 60° = $\dfrac{h}{15}$
$\sqrt{3}$ = $\dfrac{h}{15}$
h = 15$\sqrt{3}$
58694.The line drawn from the eye of an observer to the point in the object viewed by the observer is said to be
Angle of elevation
Angle of depression
Line of sight
None of the above
Explanation:
The line drawn from the eye of an observer to the point in the object viewed by the observer is said to be line of sight.
58695.The height or length of an object or the distance between two distant objects can be determined with the help of:
Trigonometry angles
Trigonometry ratios
Trigonometry identities
None of the above
Explanation:
The height or length of an object or the distance between two distant objects can be determined with the help of trigonometry ratios.
58696.If the angles of elevation of the top of a tower from two points at the distance of a m and b m from the base of tower and in the same straight line with it are complementary, then the height of the tower (in m) is
$\sqrt{(\dfrac{a}{b})}$
$\sqrt{ab}$
$\sqrt{(a + b)}$
$\sqrt{(a – b)}$
Explanation:
If the angles of elevation of the top of a tower from two points at the distance of a m and b m from the base of tower and in the same straight line with it are complementary, then the height of the tower (in m) is $\sqrt{ab}$
