Answer:
4.91 x 10⁻⁷ m
Explanation:
the applicable formula is
v = fλ
where
v = velocity (i.e speed) = given as 3.0 x 10⁸ m/s
f = frequency = given asw 6.11 x 10¹⁴
λ = wavelength
if we rearrange the equation and substitute the values given above,
v = fλ
λ = v/f
= 3.0 x 10⁸ / 6.11 x 10¹⁴
= 4.91 x 10⁻⁷ m
Answer : The correct option is, (b) Thermometer B, because it measures temperature more accurately than A.
Explanation :
Accuracy : It is defined as the closeness of a measured value to a standard or known value.
For Example: If the mass of a substance is 50 kg and one person weighed 48 kg and another person weighed 55 kg. Then, the weight measured by first person is more accurate.
Precision : It is defined as the closeness of two or more measurements to each other.
For Example: If you weigh a given substance five times and you get 1.8 kg each time. Then the measurement is said to be precise.
Level of precision is determined by the maximum number of decimal places.
As per question, the thermometer B has markings 40°, 45° and 50° at equal intervals and there are four small markings equally spaced in between the numbers and thermometer B has markings 40°, 45° and 50° at equal intervals but there is no small markings equally spaced in between the numbers. That means, thermometer B is measures temperature more accurately than thermometer A.
Hence, correct option is, (b) Thermometer B, because it measures temperature more accurately than A.
Answer:0.25 times
Explanation:
Given
Distance of satellite from earth surface=Radius of earth
Force on the satellite is F=mg'
where g'=acceleration due to gravity at that point
Distance from center of Earth=R+R=2R
Gravitational Force is given by
Force 
Force on earth surface 
Divide 1 and 2 we get
Answer: Option A
Explanation:
The potential energy decreases in the case when the charges are opposite and they attract each other.
In this case there is no external energy required in order to put the charges together.
This is so because the charges are opposite and they will attract each other. Yes, the only condition should be that the charges should be alike.
Example: a negative charge and a positive charge.
