Answer in one word or one sentence :
1. Write the value of universal gravitational constant.
2. Write the SI unit of gravitational force.
3. Define mass.
4. What are canal rays?
5. If an atom contains one electron and one proton, will it carry a charge?
6. Name the three subatomic particles.
II. Answer in Brief:
1. State universal law of gravitation.
2. Write the importance of the universal law of gravitation.
3. Write the difference between mass and weight.
4. Calculate the value of g. The mass of the earth is 6 x 10 24 kg and radius of the earth R = 6.4 X 10 6
m.
5. Write down the electron distribution of chlorine atom. How many electrons are there in the L shell?
(Atomic number of chlorine is 17)
6. Give reason for the following:
a. Nucleus of an atom is heavy and positively charged.
b. An atom is electrically neutral.
7. Define valency by taking the examples of Silicon and oxygen (Atomic number of Silicon is 14 and
oxygen is 8).
8. Draw the electron dot structure of Phosphorus and Nitrogen (Atomic number of Phosphorus is 15
and Nitrogen is 7).
III. Answer in detail:
1. The mass of the earth is 6 x 10 24 kg and that of the moon is 7.4 x 10 22 kg. If the distance between
the Earth and the moon is 3.84 x 105 km. calculate the force exerted by the earth on the moon.
2. Write the rules suggested by Bohr and Bury in-order to distribute electrons into different orbits of an
atom.
Answers
Answer:
1, the measured value of the constant is known with some certainty to four significant digits. In SI units, its value is approximately 6.674×10−11 m3⋅kg−1⋅s−2. The modern notation of Newton's law involving G was introduced in the 1890s by C. V. Boys.
2 . In SI system, gravitational unit of force is called kilogram force.
3. a large body of matter with no definite shape.
4. Canal rays are the rays of radiation which emerges in a tube which has been discharged and has the property of low pressure with voltage of high value conditions. Explanation: These canal rays are thus positive in nature of charge.
5.An electron is a negatively charged particle, whereas a proton is a positively charged particle. The magnitude of their charges is equal. Therefore, an atom containing one electron and one proton will not carry any charge.
6. protons, neutrons, and electrons
7. The valency of an element is the combining capacity of that element. The valency is determined by the number of valence electrons present in the atom of that element. Thus, the valency of silicon is four. ...
8. .............................
lll:
1. Given that,
that,Mass of the Earth m
that,Mass of the Earth m 1=6×10²⁴ kg
Mass of the Moon m2 =7.4×10²²kg
Distance between the Earth and the Moon d=3.84×10⁵km=3.84×10⁸ m
m Gravitational Constant G=6.7×10-¹¹Nm² /kg²
Now, by using Newton’s law of gravitation
F= Gm 1 m2
_______
r²
F= 6.7×10-¹¹×6×10²⁴×7.4×10²²
_____________________
(3.84×10⁸)2
F= 14.8225×10¹
____________
297.48×10³⁵
F=20.069×10¹⁹
F=20.1×10¹⁹N
Hence, the gravitational force of attraction is 20.1×10¹⁹ N
2. Rules given by Bohr - Bury for distribution of electrons: ... The maximum number of electrons present in the shell is given by the formula (2n²), where n is the orbit number or shell number. The maximum number of electrons in different shells is as follows: The first orbit or K shell will have 2 × 12 = 2 electrons.