Which of the following circular rods,(given radius r and length l)each made of the same material and whose ends are maintained at the same temperature will conduct most heat?
- r = 2r0 ; I=2l0
- r = 2r0 ; l=l0
- r = r0 ; l= l0
- r = r0 ; l=2l0
The Correct Option is B
Solution and Explanation
Heat=KA \(\triangle \,\theta_x\)
=K\(\pi\)r2\(\frac{\triangle \,\theta}{1}\)
For option B the value of H will be more.
Therefore, the correct option is (B): r = 2r0 ; l=l0
Top Questions on thermal properties of matter
- Statement--1: Liquid pressure is only exerted on solid surfaces in contact and is exerted in between the layers of liquid. Statement--2: Surface tension arises due to difference in potential energy of molecules in the bulk of liquid and at the surface.
- JEE Main - 2026
- Physics
- thermal properties of matter
Temperature of a body \( \theta \) is slightly more than the temperature of the surroundings \( \theta_0 \). Its rate of cooling \( R \) versus temperature \( \theta \) graph should be
- WBJEE - 2026
- Physics
- thermal properties of matter
- The apparent coefficient of expansion of a liquid when heated in a copper vessel is \( C \) and in a silver vessel is \( S \). If \( A \) is the linear coefficient of expansion of copper, then the linear coefficient of expansion of silver is
- WBJEE - 2026
- Physics
- thermal properties of matter
- When a part of a straight capillary tube is placed vertically in a liquid, the liquid rises upto certain height \( h \). If the inner radius of the capillary tube, density of the liquid and surface tension of the liquid decrease by \(1%\) each, then the height of the liquid in the tube will change by ________ %.
- JEE Main - 2026
- Physics
- thermal properties of matter
- A river of width 200 m is flowing from west to east with a speed of 18 km/h. A boat, moving with speed of 36 km/h in still water, is made to travel one-round trip (bank to bank of the river). Minimum time taken by the boat for this journey and also the displacement along the river bank are _________ and _________} respectively.
- JEE Main - 2026
- Physics
- thermal properties of matter
Questions Asked in NEET exam
- Given below are two statements:
Statement I: The DNA fragments extracted from gel electrophoresis can be used in the construction of recombinant DNA.
Statement II: Smaller size DNA fragments are observed near the anode while larger fragments are found near the wells in an agarose gel.- NEET (UG) - 2025
- Molecular Biology
Given below are two statements:
Statement I: Transfer RNAs and ribosomal RNA do not interact with mRNA.
Statement II: RNA interference (RNAi) takes place in all eukaryotic organisms as a method of cellular defence.
In the light of the above statements, choose the most appropriate answer from the options given below:- NEET (UG) - 2025
- RNA interference
- Given below are two statements: Statement I: In the RNA world, RNA is considered the first genetic material evolved to carry out essential life processes. RNA acts as a genetic material and also as a catalyst for some important biochemical reactions in living systems. Being reactive, RNA is unstable.
Statement II: DNA evolved from RNA and is a more stable genetic material. Its double helical strands being complementary, resist changes by evolving repair mechanisms. In the light of the above statements, choose the most appropriate answer from the options given below:- NEET (UG) - 2025
- Structure of DNA and RNA
- A microscope has an objective of focal length \(f_o = 2\) cm and an eyepiece of focal length \(f_e = 4\) cm. The tube length of the microscope is \(L = 40\) cm. If the distance of distinct vision of eye is \(D = 25\) cm, the magnification in the microscope is:
- NEET (UG) - 2025
- Optical Instruments
- Two gases A and B are filled at the same pressure in separate cylinders with movable pistons of radii \(r_A\) and \(r_B\) respectively. On supplying an equal amount of heat to both the cylinders, their pressures remain constant and their pistons are displaced by 16 cm and 9 cm respectively. If the change in their internal energies is the same, then the ratio \(r_A / r_B\) is:
- NEET (UG) - 2025
- Thermodynamics
Concepts Used:
Conductance
What is conductance?
Conductance is an expression of the ease with which electric current flows through materials like metals and nonmetals. In equations, an uppercase letter G symbolizes conductance. The standard unit of conductance is siemens (S), formerly known as mho.
What is conductance in electricity?
Conductance in electricity is considered the opposite of resistance (R). Resistance is essentially the amount of friction a component presents to the flow of current.
The conductivity of electrolytic solutions is governed by the following factors:
- Interionic attraction
- Solvation of ions
- The viscosity of the solvent
- Temperature