Ten identical cells connected in series are required to heat a wire of length \(1\) metre and radius \(r\) by \(10^\circ ~\text{C}\) in time \(t.\) How many cells will be needed to heat a wire of length \(2\) metres with the same radius by the same temperature in the same time \(t?\)
| 1. | \(20\) | 2. | \(30\) |
| 3. | \(40\) | 4. | \(10\) |
Subtopic: Grouping of Cells |
66%
Level 2: 60%+
NEET - 2013
Hints
The density of water at \(20^\circ \text{C}\) is \(998~\text{kg/m}^3\) and at \(40^\circ \text{C}\) is \(992~\text{kg/m}^3.\) The coefficient of volume expansion of water is:
| 1. | \(3 \times 10^{-4} / ^\circ\text C\) | 2. | \(2 \times 10^{-4} / ^\circ\text C\) |
| 3. | \(6 \times 10^{-4} / ^\circ\text C\) | 4. | \(10^{-4} / ^\circ\text C\) |
Subtopic: Thermal Expansion |
72%
Level 2: 60%+
NEET - 2013
Hints
Two plane mirrors are inclined at \(70^\circ.\) A ray incident on one mirror at an angle \(\theta\) after reflection falls on the second mirror and is reflected from there parallel to the first mirror. The value of \(\theta\) is:
| 1. | \(45^\circ\) | 2. | \(30^\circ\) |
| 3. | \(55^\circ\) | 4. | \(50^\circ\) |
Subtopic: Reflection at Plane Surface |
54%
Level 3: 35%-60%
NEET - 2013
Hints
In an unbiased \(\mathrm{p\text{-}n}\) junction, holes diffuse from the \(\mathrm{p\text{-}}\)regions to \(\mathrm{n\text{-}}\)regions because of:
| 1. | the attraction of free electrons of the \(\mathrm{n\text{-}}\)region. |
| 2. | the higher hole concentration in the \(\mathrm{p\text{-}}\)region than that in the \(\mathrm{n\text{-}}\)region. |
| 3. | the higher concentration of electrons is in the \(\mathrm{p\text{-}}\)region than that in the \(\mathrm{n\text{-}}\)region. |
| 4. | the potential difference across the \(\mathrm{p\text{-}n}\) junction. |
Subtopic: PN junction |
72%
Level 2: 60%+
NEET - 2013
Hints
One coolie takes \(1\) minute to raise a suitcase through a height of \(2~\text m\) but the second coolie takes \(30~\text s\) to raise the same suitcase to the same height. The powers of two coolies are in the ratio:
1. \(1:3\)
2. \(2:1\)
3. \(3:1\)
4. \(1:2\)
1. \(1:3\)
2. \(2:1\)
3. \(3:1\)
4. \(1:2\)
Subtopic: Power |
83%
Level 1: 80%+
NEET - 2013
Hints
The outer electronic configuration of Gd:
( At. No. 64)
1. 4f5 5d4 6s1
2. 4f7 5d1 6s2
3. 4f3 5d5 6s2
4. 4f4 5d5 6s1
( At. No. 64)
1. 4f5 5d4 6s1
2. 4f7 5d1 6s2
3. 4f3 5d5 6s2
4. 4f4 5d5 6s1
Subtopic: f-Block Elements- Properties & Uses |
90%
Level 1: 80%+
NEET - 2013
Hints
Accumulation of lactic acid (HC3H5O3 a monobasic acid), in tissues leads to pain and fatigue. In a 0.10 M aqueous solution, lactic acid is 3.7% dissociated. The value of the dissociation constant, Ka, for this acid, will be:
1. 1.4 × 10–5
2. 1.4 × 10–4
3. 3.7 × 10–4
4. 2.8 × 10–4
1. 1.4 × 10–5
2. 1.4 × 10–4
3. 3.7 × 10–4
4. 2.8 × 10–4
Subtopic: Ionisation Constant of Acid, Base & Salt |
71%
Level 2: 60%+
NEET - 2013
Hints
How much will the rate of reaction increase when the concentrations of A and B are both doubled, given that the order with respect to A is 2 and with respect to B is 3?
1. 12
2. 16
3. 32
4. 10
Subtopic: Order, Molecularity and Mechanism |
85%
Level 1: 80%+
NEET - 2013
Hints
Subtopic: Ellingham Diagram |
Level 3: 35%-60%
NEET - 2013
Hints
Given:
I and II are classified as:
1. Identical
2. A pair of conformers
3. A pair of geometrical isomers
4. A pair of optical isomers
 |
 |
| I | II |
1. Identical
2. A pair of conformers
3. A pair of geometrical isomers
4. A pair of optical isomers
Subtopic: Conformational Isomers |
62%
Level 2: 60%+
NEET - 2013
Hints
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