<span>Electric field repulsive for objects of like charge and attractive for opposite type of charges and for a magnet you can say that like poles repel and unlike attracts so D makes sense</span>
Answer:
A kilowatt (kW) is a unit of power.
Explanation:
The power of an object is given by :
Here,
E is the energy required
t is time
The SI unit of power is Watts and the SI unit of energy is Joule. the commercial unit of energy is kilowatt per hour.
Option (1) : A kilojoule (kJ) is a unit of power is incorrect.
Option (2) : A gigawatt (GW) is a unit of energy is incorrect.
Option (3) : A watt (W) is a unit of energy is incorrect.
Option (4) : A kilowatt x hour per year (kWh/yr) is a unit of energy is incorrect.
Option (4) : A kilowatt (kW) is a unit of power is correct.
Hence, the correct option is (d).
Better health is central to human happiness and well-being. It also makes an important contribution to economic progress, as healthy populations live longer, are more productive, and save more. Many factors influence health status and a country's ability to provide quality health services for its people.
The frequency of any wave is (wave speed) / (wavelength) .
The speed of light is 3 x 10⁸ m/s.
If the wavelength is 10 nm (10⁻⁸ m) , then the frequency is
(3 x 10⁸) / (10⁻⁸) = <em>3 x 10¹⁶ Hz</em>
That's 30 million gigahertz !
As per Einstein's theory of relativity, the closer the clock is to the source of gravitation, the slower the time passes. Clocks close to massive bodies slow down. The time difference between two events will be very large. Time difference between two clock ticks will take extremely large amount of period.
it is confirmed by tests of general relativity.
Black holes are strongly densed matter. the gravitational attraction influences the clock ticks. Atomic clocks run a little faster on aeroplanes , away from surface of earth. Very close to back hole, where attraction and gravity is extremely high, clock ticks so slow that time can be thought of as stopped...
