JEE Mains · Physics · STD 12 - 11. Dual nature of radiation and matter
In photoelectric effect an em-wave is incident on a metal surface and electrons are ejected from the surface. If the work function of the metal is 2.14 eV and stopping potential is 2 V , what is the wavelength of the em-wave ?
(Given hc \(=1242 \mathrm{eVnm}\) where h is the Planck's constant and c is the speed of light in vaccum.)
- A 300 nm
- B 400 nm
- C 600 nm
- D 200 nm
Answer & Solution
Correct Answer
(A) 300 nm
Step-by-step Solution
Detailed explanation
\(\begin{aligned} & \phi=2.14 \\ & V_S=2 \mathrm{~V} \end{aligned}\) Using photoelectric equation. \(\begin{aligned} & \frac{h c}{\lambda}=2.14+2=4.14 \mathrm{eV} \\ & \lambda=\frac{1242}{4.14}=300 \mathrm{~nm} \end{aligned}\)
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
- The output \((\mathrm{Y})\) of logic circuit given below is \(0\) only when :
JEE Mains 2024 Hard - The \(I-V\) characteristics of an electronic device shown in the figure. The device is _______.
JEE Mains 2024 Hard - A small rigid spherical ball of mass M is dropped in a long vertical tube containing glycerine. The velocity of the ball becomes constant after some time. If the density of glycerine is half of the density of the ball, then the viscous force acting on the ball will be (consider g as acceleration due to gravity)JEE Mains 2025 Medium
- A constant Power delivering machine has towed a box, which was initially at rest, along a horizontal straight line. The distance moved by the box in time \('t'\) is proportional toJEE Mains 2021 Hard
- A thin circular disc is in the \(xy\) plane as shown in the figure. The ratio of its moment of inertia about \(z\) and \(z'\) axes will be
JEE Mains 2018 Hard - \(300 \,cal\). of heat is given to a heat engine and it rejects \(225 \,cal\). of heat. If source temperature is \(227^{\circ} C\), then the temperature of sink will be____\({ }^{\circ} C\).JEE Mains 2022 Medium
More PYQs from JEE Mains
- Let \(f: \mathbb{R} \rightarrow \mathbb{R}\) be a function defined by
\(f(x)=(2+3 a) x^2+\left(\frac{a+2}{a-1}\right) x+b, a \neq 1 . \text { If }\)
\(f(x+\mathrm{y})=f(x)+f(\mathrm{y})+1-\frac{2}{7} x \mathrm{y}\), then the value of \(28 \sum_{i=1}^5|f(i)|\) isJEE Mains 2025 Medium - If \( y=y(x) \) satisfies the differential equation \( 16(\sqrt{x+9\sqrt{x}})(4+\sqrt{9+\sqrt{x}})cos~y~dy=(1+2~sin~y)dx, x>0 \) and \( y(256)=\frac{\pi}{2}, y(49)=\alpha \) then \( 2~sin~\alpha \) is equal to:JEE Mains 2026 Easy
- If \(f(t)=\int_0^\pi \frac{2 x d x}{1-\cos ^2 \sin ^2 x}, 0 < t < \pi\), then the value of \(\int_0^{\frac{\pi}{2}} \frac{\pi^2 d t}{f(t)}\) equals ..........JEE Mains 2024 Hard
- A ring and a solid sphere rotating about an axis passing through their centers have same radii of gyration. The axis of rotation is perpendicular to plane of ring. The ratio of radius of ring to that of sphere is \(\sqrt{\frac{2}{x}}\). The value of \(x\) is \(.......\)JEE Mains 2023 Medium
- If \(z = \frac{{\sqrt 3 }}{2} + \frac{i}{2}\,\,\,\left( {i = \sqrt { - 1} } \right)\), then \({\left( {1 + iz + {z^5} + i{z^8}} \right)^9}\) is equal toJEE Mains 2019 Hard
- Water of mass \(m\) gram is slowly heated to increase the temperature from \(T_1\) to \(T_2\) The change in entropy of the water, given specific heat of water is \(1 \mathrm{Jkg}^{-1} \mathrm{~K}^{-1}\), is :JEE Mains 2025 Medium