JEE Mains · Physics · STD 11 - 14. waves and sound
A toy-car, blowing its horn, is moving with a steady speed of \(5\, m/s\) , away from a wall. An observer, towards whom the toy car is moving, is able to hear \(5\, beats\) per second. If the velocity of sound in air is \(340\, m/s\), the frequency of the horn of the toy car is close to ... \(Hz\)
- A \(680\)
- B \(510\)
- C \(340\)
- D \(167\)
Answer & Solution
Correct Answer
(D) \(167\)
Step-by-step Solution
Detailed explanation
From Doppler's effect \(f(\text { direct })=f\left(\frac{340}{340-5}\right)=f_{1}\) \(f\left(b y \text { wall) } f\left(\frac{340}{340+5}\right)=f_{2}\right.\) Beats \(=\left(f_{1}-f_{2}\right)\) \(5=f\left(\frac{340}{340-5}-\frac{340}{340+5}\right)\)…
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
- Certain galvanometers have a fixed core made of non magnetic metallic material. The function of this metallic material isJEE Mains 2023 Easy
-
Two identical circular loops P and Q each of radius r are lying in parallel planes such that they have common axis. The current through P and Q are I and 4I respectively in clockwise direction as seen from O . The net magnetic field at O is:JEE Mains 2026 Easy - The current of \(5 \mathrm{~A}\) flows in a square loop of sides \(1\) \(\mathrm{m}\) is placed in air. The magnetic field at the centre of the loop is \(\mathrm{X} \sqrt{2} \times 10^{-7} \mathrm{~T}\). The value of \(\mathrm{X}\) is _______.JEE Mains 2024 Hard
- For the given circuit the current \(i\) through the battery when the key in closed and the steady state has been reached is .....\(A\)
JEE Mains 2021 Hard - A point charge \(q =1 \mu C\) is located at a distance 2 cm from one end of a thin insulating wire of length 10 cm having a charge \(Q=24 \mu C\), distributed uniformly along its length, as shown in figure. Force between q and wire is _________ N.
(Use \(\frac{1}{4 \pi \epsilon_0}=9 \times 10^9 N \cdot m ^2 / C ^2\) )
JEE Mains 2026 Easy - A circular coil of radius \(10\, cm\) is placed in a uniform magnetic field of \(3.0 \times 10^{-5}\, T\) with its plane perpendicular to the field initially. It is rotated at constant angular speed about an axis along the diameter of coil and perpendicular to magnetic field so that it undergoes half of rotation in \(0.2\,s.\) The maximum value of \(EMF\) induced (in \(\mu V\) ) in the coil will be close to the integer\(....\mu V\)JEE Mains 2020 Hard
More PYQs from JEE Mains
- A solid cylinder of mass \(m\) is wrapped with an inextensible light string and, is placed on a rough inclined plane as shown in the figure. The frictional force acting between the cylinder and the inclined plane is: [The coefficient of static friction, \(\mu_{ s },\) is \(\left.0.4\right]\)
JEE Mains 2021 Hard - If \(\alpha \) and \(\beta \) are roots of the equation \(x^2 + px + \frac {3p}{4} = 0,\) such that \(\left| {\alpha - \beta } \right| = \sqrt {10} ,\) then \(p\) belongs to the setJEE Mains 2013 Hard
- Let \(O\) be the origin, the point \(A\) be \(z_1=\sqrt{3}+2 \sqrt{2} i\), the point \(B\left(z_2\right)\) be such that \(\sqrt{3}\left|z_2\right|=\left|z_1\right|\) and \(\arg \left(z_2\right)=\arg \left(z_1\right)+\frac{\pi}{6}\). ThenJEE Mains 2025 Hard
- A \(60\; pF\) capacitor is fully charged by a \(20\; \mathrm{V}\) supply. It is then disconnected from the supply and is connected to another uncharged \(60 \;pF\) capactior is parallel. The electrostatic energy that is lost in this process by the time the charge is redistributed between them is (in \(nJ\))JEE Mains 2020 Medium
- A sample contains \(10^{-2}\, kg\) each of two substances A and \(B\) with half lives \(4 \,s\) and \(8 \,s\) respectively. The ratio of then atomic weights is \(1: 2\) The ratio of the amounts of \(A\) and \(B\) after \(16 \,s\) is \(\frac{x}{100}\). the value of \(x\) is........JEE Mains 2022 Medium
- If four distinct points with position vectors \(\vec{a}, \vec{b}, \vec{c}\) and \(\vec{d}\) are coplanar; then \([\vec{a} \vec{b} \vec{c}]\) is equal toJEE Mains 2023 Medium