All the boats operating at night requires Navigation light.
Navigation light helps prevent collisions between boats and see if visibility is poor. The types of boat are : Rowboats, Tug boats, Vessels, Sailboat etc.
Various boats have different lightning color to show its use and side of the boat.
Answer:We are usually not aware of the electric force acting between two everyday objects because most everyday objects have as many plus charges as minus charges. Option A
Explanation:An electric force is exerted between any two charged objects( either positive or negative). Objects with the same charge will repel each other, and objects with opposite charge will attract each other. The strength of the electric force between any two charged objects depends on the amount of charge that each object contains and on the distance between the two charges. Electric charges are generated all around us due to different surfaces bearing different types of charges. We are usually not aware of it because the quantity of positive charges equals the number of negative charges.
-5 is the correct answer for this!
Solution :
Magnetic field at the centre due to 
:
Its direction will be downwards in the plane of the paper.
Magnetic field at the centre due to 
:
Its direction will be upwards in the plane of the paper
Magnetic field due to the coil:
Its direction will be rightwards.
Now the resultant of the magnetic field at the centre.
Now the direction ,
Therefore 
(from right to upward)
Answer:
5501 kg/m^3
Explanation:
The value of g at the Earth's surface is
where G is the gravitational constant
M is the Earth's mass
is the Earth's radius
Solving the formula for M, we find the value of the Earth's mass:
The Earth's volume is (approximating the Earth to a perfect sphere)
So, the average density of the Earth is
