Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 17: Problem 2432

Direction Read the following question choose if: (a) Both Assertion and Reason are true and Reason is correct explanation of Assertion. (b) Both Assertion and Reason are true, but Reason is not correct explanation of Assertion. (c) Assertion is true but the Reason is false. (d) Both Assertion and Reason is false. Assertion: Metals like Na or \(\mathrm{K}\), emit electrons even when visible lights fall on them. Reason: This is because their work function is low. (A) a (B) \(\mathrm{b}\) (C) \(\mathrm{c}\) (D) d

Short Answer

Expert verified
The correct answer is (C) c.

Step by step solution

01

Examine the Assertion

The Assertion states that metals like sodium (Na) and potassium (K) emit electrons when visible light falls on them. This phenomenon, known as the photoelectric effect, occurs when light (or photons of light) collide with electrons in the metal, transferring energy and allowing the electrons to escape from the surface. The Assertion claims that this process happens in sodium and potassium when exposed to visible light specifically. We'll come back to this point after looking at the Reason.
02

Examine the Reason

The Reason attributes the Assertion to the metals' low work function. The work function is the minimum energy required to remove an electron from the surface of a metal. Metals with a low work function require less energy to remove the electrons, making it easier for them to emit electrons when exposed to light. Sodium and potassium indeed have low work functions, so the Reason is true as well.
03

Check the Relationship between the Assertion and the Reason

The actual critical part is whether low work function metals can emit electrons under visible light accordingly to the Assertion. The energy of the incoming light needs to be greater or equal to the work function for the photoelectric effect to occur. However, for metals like sodium and potassium, the work function is higher than the energy provided by visible light. Therefore, the metals will not emit electrons when exposed to visible light, and the Assertion is false.
04

Determine the Correct Option

Now that we have concluded that the Assertion is false and the Reason is true, we can identify the correct option. In this case, it is (c) Assertion is true, but the Reason is false. The correct answer is (C) c.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Light of \(4560 \AA 1 \mathrm{~mW}\) is incident on photo-sensitive surface of \(\mathrm{Cs}\) (Cesium). If the quantum efficiency of the surface is \(0.5 \%\) what is the amount of photoelectric current produced? (A) \(1.84 \mathrm{~mA}\) (B) \(4.18 \mu \mathrm{A}\) (C) \(4.18 \mathrm{~mA}\) (D) \(1.84 \mu \mathrm{A}\)

U. V. light of wavelength \(200 \mathrm{~nm}\) is incident on polished surface of Fe. work function of the surface is \(4.5 \mathrm{eV}\). Find maximum speed of phote electrons. $\left(\mathrm{h}=6.625 \times 10^{-34} \mathrm{~J} . \mathrm{s}, \mathrm{c}=3 \times 10^{8} \mathrm{~ms}^{-1}, 1 \mathrm{eV}=1.6 \times 10^{-19} \mathrm{~J}\right)$ (A) \(7.75 \times 10^{4}(\mathrm{~m} / \mathrm{s})\) (B) \(875 \times 10^{5}(\mathrm{~m} / \mathrm{s})\) (C) \(8.75 \times 10^{4}(\mathrm{~m} / \mathrm{s})\) (D) \(7.75 \times 10^{5}(\mathrm{~m} / \mathrm{s})\)

If de-Broglie wavelength of electron is increased by \(1 \%\) its momentum \(\ldots \ldots\) (A) increases by \(1 \%\) (B) decreases by \(1 \%\) (C) increased by \(2 \%\) (D) decreases by \(2 \%\)

Work functions for tungsten and sodium are \(4.5 \mathrm{eV}\) and $2.3 \mathrm{eV}\( respectively. If threshold wavelength of sodium is \)5460 \AA$, threshold wavelength for tungsten will be \(\ldots \ldots . . \AA\) (A) 528 (B) 10683 (C) 2791 (D) 5893

A proton falls freely under gravity of Earth. Its de Broglie wavelength after \(10 \mathrm{~s}\) of its motion is \(\ldots \ldots \ldots\). Neglect the forces other than gravitational force. $\left[\mathrm{g}=10\left(\mathrm{~m} / \mathrm{s}^{2}\right), \mathrm{m}_{\mathrm{p}}=1.6 \times 10^{-27} \mathrm{~kg}, \mathrm{~h}=6.625 \times 10^{-34} \mathrm{~J}_{. \mathrm{s}}\right]$ (A) \(3.96 \AA\) (B) \(39.6 \AA\) (C) \(6.93 \AA\) (D) \(69.3 \AA\)
See all solutions

Recommended explanations on English Textbooks

Language Analysis

Read Explanation

International English

Read Explanation

Textual Analysis

Read Explanation

History of English Language

Read Explanation

Single Paragraph Essay

Read Explanation

Listening and Speaking

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free