# CLASS – XI

## Unit dimension measurement Part – 5

Significant figure: Significant figure are the number of digits upto which the accuracy is maintain. Rules of significant figure: (i) All non-zero digits are significant. For example, 1.235 has four significant figures. (ii) The zeros appearing between two non-zero digits are significant. For example, 4.025 has four significant figures. (iii) All the trailing zeros after […]

## Unit dimension measurement Part – 4

Accuracy precision and error measurement: Error: There is a difference between the true value and measured value when a physical quantity is measured by an instrument as the measuring instrument is not ideal. This difference is known as error. Accuracy: Accuracy of the measurement of a physical quantity is the closeness of the measured value

## Unit dimension measurement Part – 3

Vernier calipers: Vernier calipers is used to measure length of a body. It consists of four parts. (i) Main scale: It consists of a steel metallic strip (M) graduated in centimetre and millimetre in one edge and in inches in other edge. (ii) Vernier scale. A vernier scale (V) slides on the strip M is

## Unit dimension measurement Part – 2

Measurement: 1. Parallax method: If you hold a pen in front of your eye and look the tip of the pen by closing the right eye and then the left eye keeping right eye open, you observe that the position of the tip of the pen changes. This relative shift of the tip of the

## Unit dimension measurement Part – 1

Dimension: All the physical quantities are derived from some fundamental quantities. Any physical quantity is expressed in terms of the product of different powers of the fundamental quantities. The exponent of fundamental quantities that represents the expression is called the dimension of that physical quantity. Consider a physical quantity speed = = Â = length (time)-1

## Moment Of Inertia Part 1

Moment of inertia: According to Newton’s first law of motion, if there is no external force is applied on a body, the body continuous in its state of rest or of uniform motion in a straight line. The property of the body by virtue of which it tends to resist the change its state of

## Work Energy Power Part 8

Power: power is defined as the time rate of doing work. P = Â = = = Fvcos. SI unit of power is watt = Nms-1 Dimension [P] = Â = Â = [ML2T-3]. 1 horse power (H.P.) = The amount of power is required to hold a mass of 550 lb for 1 second at a heightÂ

## Work Energy Power Part 7

Laws of conservation of mechanical energy: It state that the total mechanical energy of a system remain constant if only conservative forces are acting on the system of particles and the work done by all other forces is zero. The initial potential and kinetic energy of the system are Ui and Ki respectively. The final

## Work Energy Power Part 6

Potential energy of spring: When a spring is compressed or elongated by a force F and the elongation or compression is x, then F x. Or, F = kx [where k is the force constant of spring]Â  ——-(i) If Fe is the elastic force or restoring force applied by spring, then Fe = – kx

## Work Energy Power Part 5

Conservative and non-conservative field:Â  A force is said to be conservative if the work done by or against the force in moving a body depends only on the initial and final position of the body not the nature of the path. Gravitational force, electrostatic force between two stationary charges, spring force etc. areÂ  conservative force.

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