Coal is burned to get energy. By burning coal, green houses gases like carbon dioxide, nitrogen oxides and suphur oxides are produced.
Rest of the energy sources given in the option are clean energies.
Answer is A.
Answer:
option B
Explanation:
When you rub a clear plastic pen with the wool the plastic pen gets charges this phenomenon is known as frictional charging.
Due to rubbing, the pen gets negatively charged.
We know, opposite charge attract each other and the same charge repel each other.
So, when the pen is negatively charged the tape might be positively charged or the tape might be uncharged.
Hence, the correct answer is option B
Answer:
Explanation:
Given
Charge of first Particle 
Charge of second Particle 
distance between them 

magnetic field due to first charge at mid-way between two charged particles is



(away from it)
Electric field due to 


(towards it)

(away from first charge)
Thank you for posting your question here at brainly. A mass of m moves with 2V towards in the opposite direction of a mass, 4m moving at a speed of V, the speed of m was 2/5V and the mass of 4m was 7.5V. I hope it helps.