Q. No.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 :
1. 68 cm
2. 6.8 cm
3. 113.9 cm
4. 88 cm
Subtopic: Thermal Expansion |
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Level 1: 80%+
NEET - 2019
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A rod of length \(40\text{ cm}\) has the coefficient of linear expansion \({\mathit{\alpha}}_{1}{=}{6}\times{10}^{{-}{6}}\mathop {/}\nolimits^{\circ}{\text C} .\) Another rod of length \(l\) has the coefficient of linear expansion \({\mathit{\alpha}}_{2}{=}{4}\times{10}^{{-}{6}}\mathop {/}\nolimits^{\circ}{\text C} .\) If the difference in the lengths of the two rods always remain same at all temperatures, then the value of \(l\) is
1. \(26\text{ cm}\)
2. \(60\text{ cm}\)
3. \(80\text{ cm}\)
4. \(32\text{ cm}\)
1. \(26\text{ cm}\)
2. \(60\text{ cm}\)
3. \(80\text{ cm}\)
4. \(32\text{ cm}\)
Subtopic: Thermal Expansion |
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The coefficient of cubical expansion of water is negative between \(0^{\circ}\text{C}\) and:
1. \(4^{\circ}\text{C}\)
2. \(10^{\circ}\text{C}\)
3. \(15.5^{\circ}\text{C}\)
4. \(100^{\circ}\text{C}\)
1. \(4^{\circ}\text{C}\)
2. \(10^{\circ}\text{C}\)
3. \(15.5^{\circ}\text{C}\)
4. \(100^{\circ}\text{C}\)
Subtopic: Thermal Expansion |
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Two different wires having lengths \(L_1\) and \(L_2, \) and respective temperature coefficient of linear expansion \(\alpha_1\) and \(\alpha _2, \) are joined end-to-end. Then the effective temperature coefficient of linear expansion is:
1. \( 4 \dfrac{\alpha_1 \alpha_2}{\alpha_1+\alpha_2} \dfrac{L_2 L_1}{\left(L_2+L_1\right)^2} \)
2. \( 2 \sqrt{\alpha_1 \alpha_2} \)
3. \( \dfrac{\alpha_1+\alpha_2}{2} \)
4. \( \dfrac{\alpha_1 L_1+\alpha_2 L_2}{L_1+L_2}\)
Subtopic: Thermal Expansion |
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A copper rod of length \(1~\text{m}\) is heated from \(20^{\circ}\text{C}\) to \(120^{\circ}\text{C}.\) If the coefficient of linear expansion of copper is \(5 \times 10^{-5}{ }~^{\circ} \text{C}^{-1},\) what will be the increase in the length of the rod?
| 1. | \(2.5~\text{cm}\) | 2. | \(0.5~\text{cm}\) |
| 3. | \(7.5~\text{cm}\) | 4. | \(10~\text{cm}\) |
Subtopic: Thermal Expansion |
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Given that the coefficient of linear expansion of brass is \(\alpha=0.00002^\circ \text{C}^{-1},\) what rise in temperature is required to increase the length of a brass rod by \(1\text{%} \text{?}\)
1. \(750^\circ \text{C}\)
2. \(500^\circ \text{C}\)
3. \(200^\circ \text{C}\)
4. \(100^\circ \text{C}\)
1. \(750^\circ \text{C}\)
2. \(500^\circ \text{C}\)
3. \(200^\circ \text{C}\)
4. \(100^\circ \text{C}\)
Subtopic: Thermal Expansion |
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A unit scale is to be prepared whose length does not change with temperature and remains \(20\) cm, using a bimetallic strip made of brass and iron, each of different lengths. The length of both components would change in such a way that the difference between their lengths remains constant. If the length of the brass is \(40\) cm, then the length of the iron will be:
\(\left(\alpha_{\text {iron }}=1.2 \times 10^{-5}~ \text{K}^{-1} \text { and } \alpha_{\text {brass }}=1.8 \times 10^{-5} ~\text{K}^{-1}\right)\).
1. \(20\) cm
2. \(40\) cm
3. \(60\) cm
4. \(80\) cm
\(\left(\alpha_{\text {iron }}=1.2 \times 10^{-5}~ \text{K}^{-1} \text { and } \alpha_{\text {brass }}=1.8 \times 10^{-5} ~\text{K}^{-1}\right)\).
1. \(20\) cm
2. \(40\) cm
3. \(60\) cm
4. \(80\) cm
Subtopic: Thermal Expansion |
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A metal sheet with a circular hole is heated. The hole is:
| 1. | gets larger |
| 2. | gets smaller |
| 3. | remains of the same size |
| 4. | gets deformed |
Subtopic: Thermal Expansion |
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If the coefficient of linear expansion of a metal is \(10^{-5}/^\circ\text C,\) the coefficient of volume expansion of the same metal is:
1. \(10^{-5}/^\circ\text C\)
2. \(2\times10^{-5}/^\circ\text C\)
3. \(4\times10^{-5}/^\circ\text C\)
4. \(3\times10^{-5}/^\circ\text C\)
1. \(10^{-5}/^\circ\text C\)
2. \(2\times10^{-5}/^\circ\text C\)
3. \(4\times10^{-5}/^\circ\text C\)
4. \(3\times10^{-5}/^\circ\text C\)
Subtopic: Thermal Expansion |
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A circular metallic disc of radius \(R\) has a small circular cavity of radius \(r\) as shown in figure. Upon heating the system:
| 1. | \(R\) increases and \(r\) decreases |
| 2. | \(R\) decreases and \(r\) increases |
| 3. | Both \(R\) and \(r\) increase |
| 4. | Both \(R\) and \(r\) decrease |
Subtopic: Thermal Expansion |
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