Download App

Electric Field and Potential — Physics STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 SciencePhysicsElectric Field and Potential3 Marks
Question
Suppose an attractive nuclear force acts between two protons which may be written as $\text{F}=\text{Ce}^{-\text{kr}}/\text{r}^2.$
  1. Write down the dimensional formulae and appropriate SI units of C and k.
  2. Suppose that k = 1 fermi-1 and that the repulsive electric force between the protons is just balanced by the attractive nuclear force when the separation is 5 fermi. Find the value of C.
✓

Answer

Expression of electrical force $\text{F}=\text{C}\times\text{e}^{\frac{-\text{kr}}{\text{r}^2}}$

Since e-kr is a pure number. So, dimensional formulae of $\text{F}=\frac{\text{dimensional formulae of C}}{\text{dimensional formulae of r}^2}$

Or, $\big[\text{MLT}^{-2}\big]\big[\text{L}^2\big]=$ dimensional formulae of $\text{C}=\big[\text{ML}^3\text{T}^{-2}\big]$

Unit of C = unit of force × unit of r2 = Newton × m2 = Newton-m2

Since -kr is a number hence dimensional formulae of

$\text{k}=\frac{1}{\text{dim entional formulae of r}}=\big[\text{L}^{-1}\big]$ Unit of k = m-1

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "3 Marks Question" from Electric Field and Potential→Electric Field and Potential — all question types→Physics STD 11 Science question papers→Rajasthan Board STD 11 Science question papers→Rajasthan Board question paper generator→

Similar questions

A block of mass 100g is moved with a speed of 5.0m/s at the highest point in a closed circular tube of radius 10cm kept in a vertical plane. The cross-section of the tube is such that the block just fits in it. The block makes several oscillations inside the tube and finally stops at the lowest point. Find the work done by the tube on the block during the process.
→
The efficiency of an ideal engine is $\frac{1}{8}$ access. After reducing the temperature 100 K , increase to $\frac{1}{6}$ of access. Find the original and final temperature.
→
Consider the fusion in helium plasma. Find the temperature at which the average thermal energy 1.5kT equals the Coulomb potential energy at 2fm.
→
A car start from rest and accelerates to attains a velocity of $30 m / s$ in 12 sec . Then find (i) acceleration of that car, (ii) total distance covered, (iii) velocity after 7 sec
→
Two soap bubbles have radii 2 cm and 3 cm respectively. What would be the radius of curvature of the surface formed at the contact surface when the two bubbles are brought near each other?
→
Find the magnitude and direction of the resultant of two forces $\vec{\text{P}}$ and $\vec{\text{Q}}$ in terms of their magnitudes and angle $\theta$ between them.
→
A stone dropped from the top of a tower of height 300m splashes into the water of a pond near the base of the tower. When is the splash heard at the top given that the speed of sound in air is 340m s–1? (g = 9.8m s–2)
→
Design a logical circuit using AND, OR and NOT gates to evaluate $\text{A}\overline{\text{BC}}+\text{B}\overline{\text{CA}}.$
→
A body oscillates with SHM according to the equation (in SI unit)

$\text{x}=5\cos\Big[2\pi\text{t}+\frac{\pi}{4}\Big]$

At t = 1.5 second, calculate (i) displecement, (ii) speed.

→
A passenger arriving in a new town wishes to go from the station to a hotel located 10 km away on a straight road from the station. A dishonest cabman takes him along a circuitous path 23 km long and reaches the hotel in 28 min. What is (a) the average speed of the taxi, (b) the magnitude of average velocity? Are the two equal?
→