Tag: physics

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Multiple choice physics heat and temperature anomalous expansion of water thermal expansion in solids, liquids and gases thermal expansion

If the pendulum of a clock is made of a metal like steel or brass

  1. It's length increases in summer

  2. Time period of oscillation increases

  3. Both

  4. None
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

If the pendulum of a clock is made of a metal like steel or brass,its length increases in summer due to increase in Temperature ,hence time period of oscillation increases and the clock goes slow.

Multiple choice physics heat and temperature anomalous expansion of water thermal expansion in solids, liquids and gases thermal expansion

Coefficient of real expansion

  1. Apparent increase in volume/original volume $\times$ rise in temperature

  2. True increase in volume/ original volume $\times$ rise in temperature

  3. Both

  4. None
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The true increase in the volume of liquid per unit original volume of liquid per degree rise in temperature is called coefficient of volume expansion.

Multiple choice physics heat and temperature anomalous expansion of water thermal expansion in solids, liquids and gases thermal expansion

A heating coil is immersed in a 100g sample of $H _2O(l)$ at 1 atm and $100 \circ C$ in a closed vessel. In this heating process, 60% of the liquid is converted to the gaseous form at constant pressure of 1 atm. The densities of liquid and gaseous water under these conditions are $1000 kg / m^3$ and $0.60 kg /m^3$ respectively. Magnitude of the work done for the process is

  1. 4997 J

  2. 4970 J

  3. 9994 J

  4. 1060 J
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice physics heat and temperature anomalous expansion of water thermal expansion in solids, liquids and gases thermal expansion

A liquid column of height $80cm$ at $0^oC$ balances the same liquid of height $80.4cm$ at $100^oC$. ${\gamma} _{R}$ is

  1. $4 \times {10}^{-5}/^oC$

  2. $3 \times {10}^{-5}/^oC$

  3. $5 \times {10}^{-5}/^oC$

  4. $6 \times {10}^{-5}/^oC$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The coefficient of real expansion gamma_R is given by (h1 - h2) / (h2 * delta_T). Here, (80.4 - 80) / (80 * 100) = 0.4 / 8000 = 0.00005 = 5 * 10^-5 /C.

Multiple choice physics heat and temperature anomalous expansion of water thermal expansion in solids, liquids and gases thermal expansion

When the temperature of the body increases from t to t+Δt, its moment of inertia increases from I to I+ΔI .The coefficient of liner expansion of the body is α. The ratio ΔI/I is equal to:

  1. $ \Delta t/I$

  2. $ 2 \Delta t/I$

  3. $ \alpha \Delta t$

  4. $2 \alpha \Delta t$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Moment of inertia I is proportional to r^2, where r is a linear dimension. Thus, I is proportional to L^2. Differentiating, dI/I = 2 * dL/L. Since dL/L = alpha * delta_T, then dI/I = 2 * alpha * delta_T.

Multiple choice physics heat and temperature anomalous expansion of water thermal expansion in solids, liquids and gases thermal expansion

In Searle's apparatus we have two wires. During experiment we study the extension in one wire. The use of second wire is-

  1. to support the apparatus because it is heavy and may not break single wire

  2. to compensate the changes in length caused by changes in temperature of atmosphere during experimentation

  3. to keep the apparatus in level so that extension is measured accurately

  4. all the three above
Reveal answer Fill a bubble to check yourself
C Correct answer
Multiple choice physics heat and temperature anomalous expansion of water thermal expansion in solids, liquids and gases thermal expansion

Real expansion of liquid is :

  1. independent of expansion of the vessel

  2. dependent on expansion of the vessel

  3. independent of nature of the liquid

  4. depends on both nature of the liquid and vessel
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Real expansion is the expansion of the liquid independent of where it is contained and is a property of the liquid. Apparent expansion will depend on  the container.

Multiple choice physics heat and temperature anomalous expansion of water thermal expansion in solids, liquids and gases thermal expansion

The holes through which the fish plates are fitted to join the rails are oval in shape because :

  1. bolts are in oval shape

  2. to allow the movement of rails in the direction of length due to change in temperature

  3. to make the fitting easy and tight

  4. only oval shape holes are possible
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A fishplate is a metal bar that is bolted to the ends of two rails to join them together in a track. Because of friction between wheel and rails temperature increases. Thus a thermal expansion on rails happens. So, if rails are joined one after another without keeping any gap between them, the rails may bend. The holes through which the fish plates are fitted to join the rails are oval in shape to give sufficient space for length of the rails to increase.