Home
Class 11
MATHS
A source of light is hung h mts. Directl...

A source of light is hung h mts. Directly above a straight horizontal path on which a boy a mts. In height is walking. If a boy walks at a rate of b mts/sec. from the light then the rate at which his shadow increasese.

A

`(ab)/(h-a)mt//sec`

B

`(ab)/(h+a)mt//sec`

C

`(ab)/(2(h-a))mt//sec`

D

`(ab)/(2(h+a))mt//sec`

Text Solution

Verified by Experts

The correct Answer is:
A
Promotional Banner

Topper's Solved these Questions

  • RATE MEASUREMENT

    AAKASH SERIES|Exercise PRACTICE SHEET (EXERCISE - 1) (LEVEL - 1) (STRAIGHT OBJECTIVE TYPE QUESTION)|43 Videos

  • PROPERTIES OF VECTORS

    AAKASH SERIES|Exercise PRACTICE EXERCISES|55 Videos

  • RATE OF CHANGE

    AAKASH SERIES|Exercise Advanced Subjective Type Questions|22 Videos

Similar Questions

Explore conceptually related problems

A person of height 180 cm starts from a lamp post height 450 cm and walks at the constant rate of 4 km per hour. Find the rate at which his shadow increases.

A person of height 2mt starts from a lamp post of height 5 mt and walks away at the constant rate of 6 km per hour. The rate at which his shadow inceases is

A man of height 2 metres walks at a uniform speed of 5 km/h away from a lamp post which is 6 metres high. Find the rate at which the length of his shadow increases.

A kite flying at a height 'h' mts has ''x'' meters of string paid out at a seconds. If the kite moves horizontally with constant v mts/sec. Then the rate at which the string is paid out is

A point source of light P is placed at a distance L in front of a mirror of width d hung vertically on a wall . A man walks infront of the mirror a long a line parallel to the mirror at a distance 2L as shown in the figure. The greatest distance over which he can see the image of the light source, in the mirror is

A man 6ft. Walks at a uniform rate of 4 miles per hour away from a lamp post of 20 ft. high. Find the rate at which (i) the length of his shadow increases and (ii) the tip of his shadow moves.

A man on a wharf 20 mt above the water level, pulls in a rope to which a boat is attached, at the rate of 4 mt per second. At what rate is the boat approaching the shore, when there is still 25 mt of rope out.

AAKASH SERIES-RATE MEASUREMENT-PRACTICE SHEET (EXERCISE - 1) (LEVEL - 1) (STRAIGHT OBJECTIVE TYPE QUESTION)
  1. A variable triangle ABC is inscribed in a circle of diameter x units. ...

    Text Solution

    |

  2. An aeroplane is flying horizontally at an altitude of 3000 ft directly...

    Text Solution

    |

  3. A source of light is hung h mts. Directly above a straight horizontal ...

    Text Solution

    |

  4. If the rate of change in the perimeter of a square is K times the rate...

    Text Solution

    |

  5. The point of the ellipse 16x^(2) + 9y^(2) = 400. At which the ordinate...

    Text Solution

    |

  6. A car starts from and attains the speed of 1 km/hr nad 2,ms/hr at the ...

    Text Solution

    |

  7. A point is moving along y^(3) = 27x. The interval in which the absciss...

    Text Solution

    |

  8. In a simple pendulum , if the rate of change in the time period is equ...

    Text Solution

    |

  9. A point is moving on y = 4 - 2x^(2). The x-coordinate of the point is ...

    Text Solution

    |

  10. At the point (2,3) on the curve y = x^(3) - 2x + 1, the gradient of th...

    Text Solution

    |

  11. A point is moving along the cubical parabola 12y = x^(3). The rate of...

    Text Solution

    |

  12. Moving along the x - axis there are two points with x = 10 + 6t, x =3 ...

    Text Solution

    |

  13. The pressure p and the voluem v of a gas are connected by the relation...

    Text Solution

    |

  14. A wheel rotates so that the angle of rotation is proportional to the s...

    Text Solution

    |

  15. If the semivertical angle of a cone is 45^(@) then the rate of chang...

    Text Solution

    |

  16. The volume of a ball increases at 2pic.c//sec. The rate of increase of...

    Text Solution

    |

  17. A ballon is in the shape of a cone surmounted by a semi sphere. The ra...

    Text Solution

    |

  18. The spherical ballon is being inflated so that its volume increases un...

    Text Solution

    |

  19. If the radius of a sphere ia equal to the height and radius of the cyl...

    Text Solution

    |

  20. A rectangular vessel is of 2 mt long. 0.5 mt breadth and I mt deep. If...

    Text Solution

    |