Lakshya Education MCQs

Question: The diameter of a spare is 8 cm. It is melted and drawn into a wire of diameter 3 mm. The length of the wire is :
Options:
A.36.9 m
B.37.9 m
C.38.9 m
D.39.9 m
Answer: Option B

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Question 1. The external and internal diameters of a hemispherical bowl are 10 cm and 8 cm respectively. What is the total surface area of the bowl ?
  1.    257 cm2
  2.    286 cm2
  3.    292 cm2
  4.    302 cm2
Answer: Option B
Question 2. A pyramid has an equilateral triangle as its base of which each side is 1 m. Its slant edge is 3 m. The whole surface are of the pyramid is equal to :
  1.    $$\frac{{\sqrt 3 + 2\sqrt {13} }}{4}sq.m$$
  2.    $$\frac{{\sqrt 3 + 3\sqrt {13} }}{4}sq.m$$
  3.    $$\frac{{\sqrt 3 + 3\sqrt {35} }}{4}sq.m$$
  4.    $$\frac{{\sqrt 3 + 2\sqrt {35} }}{4}sq.m$$
Answer: Option C
Question 3. A hemisphere and a cone have equal bases. If their heights are also equal, then the ratio of their curved surface will be :
  1.    $$\sqrt 2 :1$$
  2.    $$1:\sqrt 2 $$
  3.    2 : 1
  4.    1 : 2
Answer: Option A
Question 4. If three metallic spheres of radii 6 cm, 8 cm and 10 cm are melted to from a single sphere, the diameter of the new sphere will be :
  1.    12 cm
  2.    24 cm
  3.    30 cm
  4.    36 cm
Answer: Option B
Question 5. Consider the volumes of the following
1. A parallelepiped of length 5 cm, breadth 3 cm and height 4 cm
2. A cube of each side 4 cm
3. A cylinder of radius 3 cm and length 3 cm
4. A sphere of radius 3 cm
The volumes of these in the decreasing order is :
  1.    1, 2, 3, 4
  2.    1, 3, 2, 4
  3.    4, 2, 3, 1
  4.    4, 3, 2, 1
Answer: Option D
Question 6. If the heights of two cones are in the ratio 7 : 3 and their diameters are in the ratio 6 : 7, what is the ratio of their volumes ?
  1.    3 : 7
  2.    4 : 7
  3.    5 : 7
  4.    12 : 7
Answer: Option D

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