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प्रश्न
Pick out the two scalar quantities in the following list:
Force, Angular momentum, Work, Current, Linear momentum, Electric field, Average velocity, Magnetic moment, Relative velocity.
उत्तर
Work and current are scalar quantities in the given list.
Explanation:
The work done is given by the dot product of force and displacement. Since the dot product of two quantities is always a scalar, work is a scalar physical quantity.The only thing that can describe a current is its magnitude. Its direction is not taken into account. Hence, it is a scalar quantity.
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संबंधित प्रश्न
Pick out the only vector quantity in the following list:
Read the statement below carefully and state with reason, if it is true or false:
Each component of a vector is always a scalar.
Read the statement below carefully and state with reason, if it is true or false:
The total path length is always equal to the magnitude of the displacement vector of a particle.
Read the statement below carefully and state with reason, if it is true or false:
Three vectors not lying in a plane can never add up to give a null vector.
The position of a particle is given by
`r = 3.0t hati − 2.0t 2 hatj + 4.0 hatk m`
Where t is in seconds and the coefficients have the proper units for r to be in metres.
- Find the v and a of the particle?
- What is the magnitude and direction of velocity of the particle at t = 2.0 s?
Read the statement below carefully and state, with reason and example, if it is true or false:
A scalar quantity is one that does not vary from one point to another in space.
Three vectors A, B and C add up to zero. Find which is false.
Following are four differrent relations about displacement, velocity and acceleration for the motion of a particle in general. Choose the incorrect one (s):
- `v_(av) = 1/2 [v(t_1) + v(t_2)]`
- `v_(av) = (r(t_2) - r(t_1))/(t_2 - t_1)`
- `r = 1/2 (v(t_2) - v(t_1))(t_2 - t_1)`
- `a_(av) = (v(t_2) - v(t_1))/(t_2 - t_1)`
If |A| = 2 and |B| = 4, then match the relations in column I with the angle θ between A and B in column II.
| Column I | Column II |
| (a) A.B = 0 | (i) θ = 0 |
| (b) A.B = + 8 | (ii) θ = 90° |
| (c) A.B = 4 | (iii) θ = 180° |
| (d) A.B = – 8 | (iv) θ = 60° |
The magnitude of vectors `vec"A"`, `vec"B"` and `vec"C"` are respectively 12, 5 and 13 units and `vec"A"` + `vec"B"` = `vec"C"`, then the angle between `vec"A"` and `vec"B"` is ______.
