Two rods of same material have same length an | vedclass

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

Question

(B) The heat flow is given by $\Delta Q = \frac{\Delta T}{R_{eq}} t$,where $\Delta T$ is the temperature difference and $R_{eq}$ is the equivalent the

Vedclass · Accepted Answer

$3$

Vedclass · Answer

(B) The heat flow is given by $\Delta Q = \frac{\Delta T}{R_{eq}} t$,where $\Delta T$ is the temperature difference and $R_{eq}$ is the equivalent thermal resistance.For two identical rods of resistance $R$,the series resistance is $R_{series} = R + R = 2R$.For the series case,$\Delta Q = \frac{\Delta T}{2R} 	imes 12$.When joined in parallel,the equivalent resistance is $R_{parallel} = \frac{R 	imes R}{R + R} = \frac{R}{2}$.For the parallel case,$\Delta Q = \frac{\Delta T}{R/2} 	imes t$.Equating the two expressions for $\Delta Q$: $\frac{\Delta T}{2R} 	imes 12 = \frac{\Delta T}{R/2} 	imes t$.$\frac{12}{2R} = \frac{2t}{R} \Rightarrow 6 = 2t \Rightarrow t = 3 \, 	ext{minutes}$.

Two rods of same material have same length and area. The heat $\Delta Q$ flows through them for $12 \, \text{minutes}$ when they are joined in series. If now both the rods are joined in parallel,then the same amount of heat $\Delta Q$ will flow in ........ $\text{minutes}$.

Similar Questions

$A$ circular disc of radius $R$ and thickness $\frac{R}{6}$ has a moment of inertia $I$ about an axis passing through its center and perpendicular to its plane. It is melted and recast into a solid sphere. The moment of inertia of this sphere about its diameter is:

Which one of the following pairs is incorrectly matched?

The particles emitted during the sequential radioactive decay of ${}^{238}U_{92}$ to ${}^{206}Pb_{82}$ are

$A$ tangent galvanometer has a coil of $25$ turns and a radius of $15 \, cm$. The horizontal component of the earth's magnetic field is $3 \times 10^{-5} \, T$. The current required to produce a deflection of $45^o$ in it is.....$A$

Which of the following oxides of nitrogen is a blue solid?

Vedclass Test Series

Exam Paper Generator

Online Exam Module