Question

The value of Planck's constant is

• A. \(6.626 \times 10^{-33}\ Js\)
• B. \(6.626 \times 10^{-32}\ Js\)
• C. \(6.626 \times 10^{-34}\ Js\)
• D. \(6.626 \times 10^{-31}\ Js\)

Hint:

Important scientific constants to remember:
• Planck's constant: \[ h = 6.626 \times 10^{-34}\ Js \]
• Avogadro number: \[ 6.023 \times 10^{23} \]
• Speed of light: \[ 3 \times 10^8\ m/s \]

Answer 1

The Correct Option is C

Concept:
Planck's constant is one of the most important constants in modern physics and quantum mechanics. It is represented by the symbol: \[ h \] It relates the energy of a photon to its frequency using the equation: \[ E = h\nu \] where:
• \(E\) = Energy of photon
• \(h\) = Planck's constant
• \(\nu\) = Frequency of radiation The accepted SI value of Planck's constant is: \[ \boxed{6.626 \times 10^{-34}\ Js} \]

Step 1: Understand the importance of Planck's constant.
Planck introduced this constant while explaining black body radiation. Later, it became a fundamental quantity in:
• Quantum mechanics
• Photoelectric effect
• Atomic structure
• Photon energy calculations The value is extremely small because energy at atomic level is very tiny.

Step 2: Recall the standard value.
The exact standard value commonly used in chemistry and physics is: \[ h = 6.626 \times 10^{-34}\ Js \]

Step 3: Compare with the options.
Among the given options: \[ \boxed{6.626 \times 10^{-34}\ Js} \] matches the standard value. Hence the correct option is: \[ \boxed{(3)\ 6.626 \times 10^{-34}\ Js} \]