Revision: Class 12 >> Experimental Skills NEET (UG) Experimental Skills

One metre is defined as 1,650,763.73 times the wavelength of a specified orange-red spectral line in emission spectrum of Krypton = 86.
OR
One metre is defined as 1,553,164.1 times the wavelength of the red line in the emission spectrum of cadmium.

“The pitch of a screw is the distance moved by the screw in one complete rotation of its head.”
OR
Pitch may also be defined as “the distance between two consecutive threads of screw measured along the axis of the screw.”

Pitch = `"Distance moved by thimble on M.S."/"Number of rotations of thimble"`

One metre is defined as the one ten-millionth part of distance from the pole to the equator.

Least count of a vernier callipers is the difference between one main scale division (M.S.D.) and one vernier scale division (V.S.D.)

A simple pendulum whose period is two seconds is called a second's pendulum.

A simple pendulum whose period of oscillation is exactly two seconds is called a second’s pendulum.

An ideal simple pendulum consists a point mass suspended from a perfectly rigid support by weightless, inextensible and perfectly flexible fibre.

An ideal simple pendulum is a heavy particle suspended by a massless, inextensible, flexible string from a rigid support.

A heavy but small sized metallic bob suspended by a light, inextensible and flexible string, which performs oscillatory motion, is called a simple pendulum.

The viscous force acting per unit area between two layers of liquid moving with unit velocity gradient is called the coefficient of viscosity (η).

The specific heat capacity of a substance is the amount of heat energy required to raise the temperature of unit mass of that substance through 1°C (or 1 K).

OR

Heat capacity of a body when expressed for the unit mass is called the specific heat capacity of the substance of that body.

OR

The amount of heat energy required to raise the temperature of a unit mass of an object by 1 °C is called the specific heat of that object.

OR

The amount of heat per unit mass absorbed or given out by a substance to change its temperature by one unit (one degree), i.e., 1°C or 1 K, is called specific heat capacity.

OR

The quantity of heat required to raise the temperature of a unit mass of a gas by one degree, whose exact value depends upon the mode of heating the gas and can range from zero to infinity or even be negative, is called the specific heat capacity of a gas.

The heat capacity of a body is the quantity of heat required to raise its temperature by 1°C. It depends upon the mass and the nature of the body.

The quantity of heat needed to raise the temperature of the whole body by 1°C (or 1 K) is called heat capacity.

T = 2π\[\sqrt {\frac {l}{g}}\]

n = \[\frac {1}{2π}\]\[\sqrt {\frac {g}{l}}\]

T = 2π\[\sqrt {\frac {L_s}{g}\] = 2 seconds

Specific heat capacity c = \[\frac{\text{Heat capacity of body } C'}{\text{Mass of the body } m}\]

or

Specific heat capacity c = \[\frac{Q}{m\times\Delta t}\]

• Heat energy absorbed (Q) depends on: mass (m), rise in temperature (Δt), and specific heat capacity (c), i.e., Q ∝ m × Δt × c.
• Heat capacity (C') and specific heat capacity (c) are related by: C′ = m × c.