JEE Mains · Physics · STD 12 - 11. Dual nature of radiation and matter
The difference between threshold wavelengths for two metal surfaces \(A\) and \(B\) having work function \(\phi_A=9\,eV\) and \(\phi_{ B }=4.5\,eV\) in \(nm\) is:(Given, \(hc =1242\,eV\,nm\))
- A \(264\)
- B \(138\)
- C \(276\)
- D \(540\)
Answer & Solution
Correct Answer
(B) \(138\)
Step-by-step Solution
Detailed explanation
\(\lambda_{ A }=\left(\frac{1242}{9}\right)=138\,nm\) \(\lambda_{ B }=\left(\frac{1242}{4.5}\right)=276\,nm\) \(\lambda_{ B }-\lambda_{ A }=138\,nm\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- A sample contains mixture of helium and oxygen gas. The ratio of root mean square speed of helium and oxygen in the sample is _______.JEE Mains 2024 Hard
- When a car is approaching the observer, the frequency of horn is \(100 Hz\). After passing the observer, it is \(50\,Hz\). If the observer moves with the car, the frequency will be \(\frac{ x }{3} Hz\) where \(x =.....\)JEE Mains 2022 Hard
- A parallel plate capacitor having capacitance \(12\, pF\) is charged by a battery to a potential difference of \(10\, V\) between its plates. The charging battery is now disconnected and a porcelain slab of dielectric constant \(6.5\) is slipped between the plates. The work done by the capacitor on the slab is.......\(pJ\)JEE Mains 2019 Hard
- A tightly wound long solenoid carries a current of 1.5 A . An electron is executing uniform circular motion inside the solenoid with a time period of 75 ns . The number of turns per metre in the solenoid is ________.
[Take mass of electron \(\mathrm{m}_{\mathrm{e}}=9 \times 10^{-31} \mathrm{~kg}\), charge of electron \(\left|\mathrm{q}_{\mathrm{e}}\right|=1.6 \times 10^{-19} \mathrm{C}\),
\(\left.\mu_0=4 \pi \times 10^{-7} \frac{\mathrm{~N}}{\mathrm{~A}^2}, 1 \mathrm{~ns}=10^{-9} \mathrm{~s}\right]\)JEE Mains 2025 Easy - The torque due to the force \((2 \hat{i}+\hat{j}+2 \hat{k})\) about the origin, acting on a particle whose position vector is \((\hat{i}+\hat{j}+\hat{k})\), would beJEE Mains 2025 Easy
- An object of mass 1000 g experiences a time dependent force \(\vec{F}=\left(2 t \hat{i}+3 t^2 \hat{j}\right) N\). The power generated by the force at time \(t\) is :JEE Mains 2025 Medium
More PYQs from JEE Mains
- Consider two sets \(A =\{ x \in z :|(| x -3|-3)| \leq 1\}\) and \(B=\left\{x \in R -\{1,2\}: \frac{(x-2)(x-4)}{x-1} \log _e(|x-2|)=0\right\}\). Then the number of onto functions \( f:A\rightarrow B \) is equal to:JEE Mains 2026 Easy
- The value of \(\left(\frac{1+\sin \frac{2 \pi}{9}+i \cos \frac{2 \pi}{9}}{1+\sin \frac{2 \pi}{9}-i \cos \frac{2 \pi}{9}}\right)^{3}\) isJEE Mains 2020 Hard
- Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : The radius vector from the Sun to a planet sweeps out equal areas in equal intervals of time and thus areal velocity of planet is constant.
Reason (R) : For a central force field the angular momentum is a constant.
In the light of the above statements, choose the most appropriate answer from the options given below :JEE Mains 2025 Easy - Three vectors \(\overrightarrow{\mathrm{OP}}, \overrightarrow{\mathrm{OQ}}\) and \(\overrightarrow{\mathrm{OR}}\) each of magnitude \(A\) are acting as shown in figure. The resultant of the three vectors is \(A \sqrt{x}\). The value of \(x\) is _______.
JEE Mains 2024 Hard - A bag is gently dropped on a conveyor belt moving at a speed of \(2\,m / s\). The coefficient of friction between the conveyor belt and bag is \(0.4\) Initially, the bag slips on the belt before it stops due to friction. The distance travelled by the bag on the belt during slipping motion is \(.....m\) [Take \(g=10\,m / s ^{-2}\) ]JEE Mains 2022 Medium
- Let \(\alpha \) and \(\beta \) be the roots of the quadratic equation \({x^2}\,\sin \,\theta - x\,\left( {\sin \,\theta \cos \,\,\theta + 1} \right) + \cos \,\theta = 0\,\left( {0 < \theta < {{45}^o}} \right)\) , and \(\alpha < \beta \). Then \(\sum\limits_{n = 0}^\infty {\left( {{\alpha ^n} + \frac{{{{\left( { - 1} \right)}^n}}}{{{\beta ^n}}}} \right)} \) is equal toJEE Mains 2019 Hard