the internal and external diameter of a hollow hemispherical vessel are 12cm&10cm. the cost of painting is rupees 2 per sqm. find the cost of painting it all over.
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the internal and external diameter of a hollow hemispherical vessel are 12cm&10cm. the cost of painting is rupees 2 per sqm. find the cost of painting it all over.
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Answer:
Mercury is the closest planet to the Sun, with an average distance of 35,000,000 miles. It takes light about 3 minutes to travel from the Sun to Mercury.
Neptune is the farthest, with an average distance of 2.8 × 109 miles from the Sun.
How many times farther from the Sun is Neptune than Mercury? How long does it take light to reach Neptune? Follow the steps to find out.
1. Write the distance from the Sun to Mercury in scientific notation. Include units with your answer.
2. Write and simplify an expression showing how many times farther Neptune is from the Sun than Mercury. Write the result in scientific notation.
Answer:
Internal diameter of spherical vessel =24 cm
External diameter of hemispherical vessel =25 cm
Internal radius =r=12 cm and External radius =R=12.5 cm
Total surface area to be painted
= External curved surface + Internal curved surface + Area of ring
=2πR
2
+2πr
2
+π(R
2
−r
2
)
=π(2R
2
+2r
2
+R
2
−r
2
)
=π(3R
2
+r
2
)
=
7
22
(3×12.5
2
+12
2
)
=
7
22
(468.75+144)
=
7
22
×612.75
=1925.78sq.cm
Rate of painting =5paise per sq.cm
Thus, cost of painting=Area×Rate=
100
1925.78×5
=Rs.96.29