A bulb is rated at 150 watt, converting 8% energy into light. If energy of one photon is 4.42 x 10-19 J, how many…

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Solution & Explanation

Related Formula

Etotal = P \times t

Elight = Etotal \times Efficiency

Elight = n \times hν

Core Logic

Power of bulb = $150 W = 150 J/s$ $150 \text{ W} = 150 \text{ J/s}$. Energy emitted in 1 second ( $t = 1 s$ $t = 1 \text{ s}$) = $150 J$ $150 \text{ J}$. Energy converted to light = $8%$ $8\%$ of $150 J$ $150 \text{ J}$.

Elight = (150 \times 8)/(100) = 12 J

Given energy of one photon ( $hν$ $h\nu$) = $4.42 \times 10⁻¹⁹ J$ $4.42 \times 10^{-19} \text{ J}$.

Step 1: Calculate number of photons

n = Elighthν

n = 124.42 \times 10⁻¹⁹

n \approx 2.714 \times 10¹⁹

Pattern Recognition

Watts = Joules/second. When finding photons per second, first reduce the total wattage by the efficiency percentage to find the "effective" light power, then divide by the energy of a single photon.

Chapter Mix

Class 11 Chemistry: Structure of Atom

More Structure of Atom Previous-Year Questions

Q50 neet_2026_03_may_morning Quantum Numbers

I

represents the subshell, for which the values are as following :

l	Subshell
0	s
1	p
2	d
3	f

Match List I with List II :

List-I (Quantum Numbers)			List-II (Orbital)
	'n'	'l'
A.	2	1	(I)	3d
B.	4	0	(II)	2p
C.	5	3	(III)	4s
D.	3	2	(IV)	5f

Choose the correct answer from the options given below.

A. A-II, B-III, C-IV, D-I
B. A-I, B-II, C-III, D-IV
C. A-IV, B-II, C-III, D-I
D. A-II, B-III, C-I, D-IV

Solution

Core Logic

The orbital is designated by combining the principal quantum number $n$ $n$ and the letter for the azimuthal quantum number $l$ $l$. Given: $l = 0 s$ $l = 0 \implies s$ $l = 1 p$ $l = 1 \implies p$ $l = 2 d$ $l = 2 \implies d$ $l = 3 f$ $l = 3 \implies f$

A. $n = 2, l = 1 2p$ $n = 2, l = 1 \implies 2p$ B. $n = 4, l = 0 4s$ $n = 4, l = 0 \implies 4s$ C. $n = 5, l = 3 5f$ $n = 5, l = 3 \implies 5f$ D. $n = 3, l = 2 3d$ $n = 3, l = 2 \implies 3d$

Step 1: Final Match

A $arrow$ $\rightarrow$ II (2p) B $arrow$ $\rightarrow$ III (4s) C $arrow$ $\rightarrow$ IV (5f) D $arrow$ $\rightarrow$ I (3d)

Pattern Recognition

Orbital notation always places the integer $n$ $n$ followed by the $s,p,d,f$ $s,p,d,f$ designation corresponding to $l = 0,1,2,3$ $l = 0,1,2,3$ respectively.

Chapter Mix

Class 11 Chemistry: Structure of Atom

A bulb is rated at 150 watt, converting 8% energy into light. If energy of one photon is $4.42 \times 10⁻¹⁹$ $4.42 \times 10^{-19}$ J, how many photons are emitted by the bulb per second?

Solution & Explanation

Related Formula

Core Logic

Step 1: Calculate number of photons

Pattern Recognition

Chapter Mix

Reference Study Guides

More Structure of Atom Previous-Year Questions

Solution

Core Logic

Step 1: Final Match

Pattern Recognition

Chapter Mix

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A bulb is rated at 150 watt, converting 8% energy into light. If energy of one photon is 4.42 × 10⁻¹⁹$4.42 \times 10^{-19}$ J, how many photons are emitted by the bulb per second?

Solution & Explanation

Related Formula

Core Logic

Step 1: Calculate number of photons

Pattern Recognition

Chapter Mix

Reference Study Guides

More Structure of Atom Previous-Year Questions

Solution

Core Logic

Step 1: Final Match

Pattern Recognition

Chapter Mix

More Structure of Atom Questions — neet_2026_03_may_morning

Select Your Target Exam

Full Mock Test Hub

Topic-wise Practice Hub

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Chapter Weightage & Trends

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A bulb is rated at 150 watt, converting 8% energy into light. If energy of one photon is $4.42 \times 10⁻¹⁹$ $4.42 \times 10^{-19}$ J, how many photons are emitted by the bulb per second?