An organ pipe 40cm long is open at both ends. The speed of sound in air is 360ms-1 . The frequency of the second harmonic is ____Hz.
Correct Answer: 900
Solution and Explanation
Step 1: Formula for frequency in an open organ pipe.- Fundamental frequency f1 = $\frac{v}{2L}$, where v = 360m/s, L = 0.4m.- Frequency of second harmonic f2 = 2f1.
Step 2: Calculate the frequency.
f1 = $\frac{360}{2 \times 0.4}$ = 450Hz.
f2 = 2 × 450 = 900Hz.
Final Answer: The frequency of the second harmonic is 900Hz
Top Questions on sound
- Equal volumes of water are added to three cylindrical jars A, B and C of the same height and radii \(r_A\), \(r_B\) and \(r_C\) respectively with \(r_A<r_B<r_C\). If you blow across the mouth of these jars, which tube will produce the shrillest note?
- Two persons A and B are standing in front of a cliff in the same line 170 m apart as shown in the diagram. Person B fires the gun and hears the echo in 3 s. Then the person A standing in front of the person B fires the gun. (The speed of sound in air is 340 m/s.)
(a) Calculate:
1. the distance of the person B from the cliff.
2. the minimum time in which B hears the gunshot fired by A.
(b) Fill in the blank. The echo is softer (less loud) than the original sound due to the decrease in __________ of the wave. (amplitude / frequency)
- (a) One end of a plastic foot ruler is held tightly at the edge of a table and the other end is plucked. Name the vibrations produced in the ruler.
(b) Now the ruler is pushed inside partially and plucked again from its free end. State with a reason whether the frequency of vibration increases or decreases.
- (a) Define natural vibrations.
(b) How is this vibration different from damped vibrations in terms of their amplitudes?
- Complete the following: Quality of sound depends on its __________.
Questions Asked in JEE Main exam
The heat generated in 1 minute between points A and B in the given circuit, when a battery of 9 V with internal resistance of 1 \(\Omega\) is connected across these points is ______ J.
- JEE Main - 2026
- Current electricity
- Let $\vec{a}=2\hat{i}-\hat{j}-\hat{k}$, $\vec{b}=\hat{i}+3\hat{j}-\hat{k}$ and $\vec{c}=2\hat{i}+\hat{j}+3\hat{k}$. Let $\vec{v}$ be the vector in the plane of $\vec{a}$ and $\vec{b}$, such that the length of its projection on the vector $\vec{c}$ is $\dfrac{1}{\sqrt{14}}$. Then $|\vec{v}|$ is equal to
- JEE Main - 2026
- Vector Algebra
The given circuit works as:
- JEE Main - 2026
- Semiconductor electronics: materials, devices and simple circuits
- Two tuning forks \(A\) and \(B\) are sounded together giving rise to 8 beats in 2 s. When fork \(A\) is loaded with wax, the beat frequency is reduced to 4 beats in 2 s. If the original frequency of tuning fork \(B\) is \(380\ \text{Hz}\), find the original frequency of tuning fork \(A\). Given: \[ f_B = 380\ \text{Hz} \]
- JEE Main - 2026
- General Physics
Let the lines $L_1 : \vec r = \hat i + 2\hat j + 3\hat k + \lambda(2\hat i + 3\hat j + 4\hat k)$, $\lambda \in \mathbb{R}$ and $L_2 : \vec r = (4\hat i + \hat j) + \mu(5\hat i + + 2\hat j + \hat k)$, $\mu \in \mathbb{R}$ intersect at the point $R$. Let $P$ and $Q$ be the points lying on lines $L_1$ and $L_2$, respectively, such that $|PR|=\sqrt{29}$ and $|PQ|=\sqrt{\frac{47}{3}}$. If the point $P$ lies in the first octant, then $27(QR)^2$ is equal to}
- JEE Main - 2026
- Three Dimensional Geometry