Answer:
Explanation:
Let q be the charges on each spheres , 2d be the distance between them in equilibrium , T be tension in the string and F be the force of repulsion between them
F = k q² /4d²
For equilibrium
T sin15 = F
T cos 15 = mg
tan15 = F / mg
F = mg tan15
k q² /4d² = mg tan15
k q² = 4d² x mg tan15
= 4 x( .7 sin15)² x 3.1 x 10⁻³ x 9.8 x .2679
= 1.068 x 10⁻³
q = .3444 x 10⁻⁶ C
no of electrons
= .3444 x 10⁻⁶ / 1.6 x 10⁻¹⁹
= 215.25 x 10¹⁰
1) In first case, both the objects(hand & tea) are in direct contact, so heat will flow by the process of "Conduction"
2) In this case, objects are not in direct contact, and heat is transferring from one to another by "Convection"
3) Here, there is no contact between the objects (our body & sun), sun light with heat comes through the process of "Radiation"
In short, Your Answers would be:
1) Conduction
2) Convection
3) Radiation
Hope this helps!
Magnetic field outside it due to long wire is given by

Magnetic field due to long wire inside wire at any point

Now the ratio of two magnetic field is given by



R = 5.3 mm
Answer:d
Explanation:
Given
First car is moving towards east with velocity 20 m/s

then it turns towards north then velocity is

suppose car takes t sec to change its path so average acceleration is given by


So average acceleration is towards North of west.
Answer:
The principle of conservation of energy and angular momentum
Explanation:
At point A, the car experienced maximum of potential energy
As it moves down the hill, the potential energy decreases while the kinetic energy increases.
The maximum kinetic energy of the car is needed for the attainment of enough centripetal force to help the car move through the loop without falling .