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 NEET Physics Questions
A constant voltage of 50 V is maintained between the points A and B of the circuit shown in the figure. The current through the branch CD of the circuit is :
- NEET (UG) - 2025
- Physics
- Current electricity
AB is a part of an electrical circuit (see figure). The potential difference \(V_A - V_B\), at the instant when current \(i = 2\) A and is increasing at a rate of 1 amp/second is:
- NEET (UG) - 2025
- Physics
- Electromagnetic Induction and Inductance
- The kinetic energies of two similar cars A and B are 100 J and 225 J respectively. On applying brakes, car A stops after 1000 m and car B stops after 1500 m. If \(F_A\) and \(F_B\) are the forces applied by the brakes on cars A and B, respectively, then the ratio \( \frac{F_A}{F_B} \) is:
- NEET (UG) - 2025
- Physics
- Work and Kinetic Energy
A full wave rectifier circuit with diodes (\(D_1\)) and (\(D_2\)) is shown in the figure. If input supply voltage \(V_{in} = 220 \sin(100 \pi t)\) volt, then at \(t = 15\) msec:
- NEET (UG) - 2025
- Physics
- Semiconductor Diode
- 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
- Physics
- Optical Instruments
Top NEET thermal properties of matter Questions
- The energy that will be ideally radiated by a 100 kW transmitter in 1 hour is:
- NEET (UG) - 2023
- Physics
- thermal properties of matter
- A cup of coffee cools from 90°C to 80°C in t minutes, when the room temperature is 20°C. The time taken by a similar cup of coffee to cool from 80°C to 60°C at a room temperature same at 20°C is
- NEET (UG) - 2021
- Physics
- thermal properties of matter
- A copper rod of $88 \,cm$ and an aluminium rod of unknown length have their increase in length independent of increase in temperature. The length of aluminium rod is $(a_{C_{u}}=1.7 \times 10^{-5}\,K^{-1}$ and $\left.a_{A_{l}}=2.2 \times 10^{-5} K^{-1}\right)$
- NEET (UG) - 2019
- Physics
- thermal properties of matter
- A spherical black body with a radius of $12\,cm$ radiates $450\,watt$ power at $500\,K$. If the radius were halved and the temperature doubled, the power radiated in watt would be :
- NEET (UG) - 2017
- Physics
- thermal properties of matter
Two rods \(A\) and \(B\) of different materials are welded together as shown in figure. Their thermal conductivities are \(K_1\) and \(K_2\). The thermal conductivity of the composite rod will be :
- NEET (UG) - 2017
- Physics
- thermal properties of matter
Top NEET Questions
- With the help of the given pedigree, find out the probability for the birth of a child having no disease and being a carrier (has the disease mutation in one allele of the gene) in the F3 generation.
- NEET (UG) - 2025
- Genetics
- Which of the following enzyme(s) are NOT essential for gene cloning?
A. Restriction enzymes
B. DNA ligase
C. DNA mutase
D. DNA recombinase
E. DNA polymerase- NEET (UG) - 2025
- Molecular Biology
A constant voltage of 50 V is maintained between the points A and B of the circuit shown in the figure. The current through the branch CD of the circuit is :
- NEET (UG) - 2025
- Current electricity
- Frogs respire in water by skin and buccal cavity and on land by skin, buccal cavity and lungs.
- NEET (UG) - 2025
- Animal Physiology
Which of the following statements are true?
A. Unlike Ga that has a very high melting point, Cs has a very low melting point.
B. On Pauling scale, the electronegativity values of N and C are not the same.
C. $Ar, K^{+}, Cl^{–}, Ca^{2+} and S^{2–}$ are all isoelectronic species.
D. The correct order of the first ionization enthalpies of Na, Mg, Al, and Si is Si $>$ Al $>$ Mg $>$ Na.
E. The atomic radius of Cs is greater than that of Li and Rb.
Choose the correct answer from the options given below:- NEET (UG) - 2025
- Inorganic chemistry
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