A film of water is formed between two straigh | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) The length of the wires is $l = 10\,cm = 0.1\,m$.Initially,the separation is $d_1 = 0.5\,cm = 0.005\,m$.Finally,the separation is $d_2 = 0.5\,cm +

Vedclass · Accepted Answer

$1.44 	imes 10^{-5}\,J$

Vedclass · Answer

(B) The length of the wires is $l = 10\,cm = 0.1\,m$.Initially,the separation is $d_1 = 0.5\,cm = 0.005\,m$.Finally,the separation is $d_2 = 0.5\,cm + 0.1\,cm = 0.6\,cm = 0.006\,m$.$A$ water film has two surfaces,so the change in area $\Delta A$ is given by $2 	imes l 	imes (d_2 - d_1)$.$\Delta A = 2 	imes 0.1\,m 	imes (0.006\,m - 0.005\,m) = 0.2 	imes 0.001 = 2 	imes 10^{-4}\,m^2$.The work done $W$ is equal to the change in surface energy: $W = T 	imes \Delta A$.Given $T = 7.2 	imes 10^{-2}\,N/m$.$W = 7.2 	imes 10^{-2} 	imes 2 	imes 10^{-4} = 14.4 	imes 10^{-6} = 1.44 	imes 10^{-5}\,J$.

$A$ film of water is formed between two straight parallel wires of length $10\,cm$ each,separated by $0.5\,cm$. If their separation is increased by $1\,mm$ while still maintaining their parallelism,how much work will have to be done? (Surface tension of water = $7.2 \times 10^{-2}\,N/m$)

Similar Questions

If $A+B+C=270^{\circ}$,then $\cos 2A+\cos 2B+\cos 2C$ is equal to:

An inductance of $\frac{200}{\pi} \ mH$,a capacitance of $\frac{10^{-3}}{\pi} \ F$ and a resistance of $10 \ \Omega$ are connected in series with an $AC$ source of $220 \ V, 50 \ Hz$. The phase angle of the circuit is:

In the circuit shown,the reading of the Ammeter is doubled after the switch is closed. Each resistor has a resistance $1\,\Omega$ and the ideal cell has an $e.m.f.$ $10\,V$. Then,the Ammeter has a coil resistance equal to ............... $\Omega$.

$A$ conducting ring is placed around the core of an electromagnet as shown in the figure. When key $K$ is pressed,the ring

The formal charges of $C$ and $O$ atoms in $CO_2$ $(\ddot{O}=C=\ddot{O})$ are,respectively

Vedclass Test Series

Exam Paper Generator

Online Exam Module