This question is based on the fundamental assumption of vector direction.
A vector is a physical quantity which has magnitude as well direction for its complete specification.
The magnitude of a physical quantity is simply a numerical number .Hence it can not be negative.
A negative vector is a vector which comes into existence when it is opposite to our assumed direction with respect to any other vector. For instance, the vector is taken positive if it is along + X axis and negative if it is along - X axis.
As per the first option it is given that a vector is negative if its magnitude is greater than 1. It is not correct as magnitude play no role in it.
The second option tells that the magnitude of the vector is less than 1. Magnitude can not be negative. So this is also wrong.
Third one tells that a vector is negative if its displacement is along north. It does not give any detail information about the negativity of a vector.
In a general sense we assume that vertically downward motion is negative and vertically upward is positive. In case of a falling object the motion is vertically downward. So the velocity of that object is negative .
So last option is partially correct as the vector can be negative depending on our choice of co-ordinate system.
Answer:
Explanation:
Given that
The speed of the airplane ,v= 142 m/s
The speed of the air ,u = 30 m/s
Lets take angle make by airplane from east direction towards north direction is θ .
Now by using diagram ,we can say that
Now by putting the values in the above equation we get
Therefore the angle will be 12.19° .
Answer:
gamma rays < X-ray < ultraviolet ray < visible light < infrared < radio wave
Explanation:
given light form,
A) radio waves,B) infrared,C) visible light,D) ultraviolet,E) X-rays,F) gamma rays
we know,
wavelength of radio wave = 10000 Km
wavelength of infrared = 700 nanometers (nm) to 1 millimeter (mm)
wavelength of visible light = 380 to 740 nm
wavelength of ultraviolet ray = 10 nm to 400 nm
wavelength of X-ray = 0.01 to 10 nm
wavelength of gamma rays = 100 picometer
so, the order of rays.
gamma rays < X-ray < ultraviolet ray < visible light < infrared < radio wave
Answer:
the total mass is 35 kg
k.E = 1/2 mv2
43.76 =1/2 v2
v2=2×43.76
Explanation:
v=radicls 87.52 which is equal to 9.5 m/s
Answer:
1/4 λ film
Explanation:
Let L = total path length then L = 2 t where t is film thickness
There will be a 180 deg phase change at the air-film interface but no
phase change at the film-air interface
L = n * wavelength / 2 where n = 1, 3, 5, 7 etc
(the total path L must be an odd number of 1/2 wavelengths)
Or t = n * wavelength / 4 (the film must be an odd number
of 1/4 wavelengths thick)
1/4 λ film satisfies this condition
Note: Find the missing diagram in the attachment section.
