Friday, 10 October 2014


1.In Hindu chronology, the longest time measure is a para. One para equals311 040 000 000 000 years.
   Calculate this value in megahours and in nanoseconds.Write your answers in scientific notation.

2. One light-year is the distance light travels in one year. This distance is equal to 9.461 × 1015 m. After the sun, the star nearest to Earth is Alpha Centauri, which is about 4.35 light-years from Earth. Express this distance in
a. megameters.
b. picometers.

3. It is estimated that the sun will exhaust all of its energy in about ten
billion years. By that time, it will have radiated about 1.2 × 1044 J (joules)
of energy. Express this amount of energy in
a. kilojoules.
b. nanojoules.
4. The smallest living organism discovered so far is called a mycoplasm. Its
mass is estimated as 1.0 × 10–16 g. Express this mass in
a. petagrams.
b. femtograms.
c. attograms.
5. The “extreme” prefixes that are officially recognized are yocto, which indicates
a fraction equal to 10–24, and yotta, which indicates a factor equal
to 1024. The maximum distance from Earth to the sun is 152 100 000 km.
Using scientific notation, express this distance in
a. yoctometers (ym).
b. yottameters (Ym).
6. In 1993, the total production of nuclear energy in the world was
2.1 × 1015 watt-hours, where a watt is equal to one joule (J) per second.
Express this number in
a. joules.
b. gigajoules.
7. In Einstein’s special theory of relativity, mass and energy are equivalent.
An expression of this equivalence can be made in terms of electron volts
(units of energy) and kilograms, with one electron volt (eV) being equal
to 1.78 × 10–36 kg. Using this ratio, express the mass of the heaviest
mammal on earth, the blue whale, which has an average mass of
1.90 × 105 kg, in
a. mega electron volts.
b. tera electron volts.
8. The most massive star yet discovered in our galaxy is one of the stars
in the Carina Nebula, which can be seen from Earth’s Southern
Hemisphere and from the tropical latitudes of the Northern Hemisphere.
The star, designated as Eta Carinae, is believed to be 200 times as massive
as the sun, which has a mass of nearly 2 × 1030 kg. Find the mass of Eta
Carinae in
a. milligrams.
b. exagrams.
9. The Pacific Ocean has a surface area of about 166 241 700 km2 and an
average depth of 3940 m. Estimate the volume of the Pacific Ocean in
a. cubic centimeters.
b. cubic millimeters.