1. A
   focal length goes to infinity.
2. B
   focal length goes to zero.
3. C
   image distance goes to zero.
4. D
   image distance goes to infinity.

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1. A
   nuclear fission and its expression was proposed by Einstein.
2. B
   nuclear fission and its expression was proposed by Rutherford.
3. C
   nuclear fusion and its expression was proposed by Bohr.
4. D
   nuclear fusion and its expression was proposed by Heisenberg.

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1. A
   multiple refraction of sound.
2. B
   multiple reflection of sound.
3. C
   single refraction of sound.
4. D
   single reflection of sound.

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1. A
   Sound can travel in vacuum and it is a transverse wave in air.
2. B
   Sound cannot travel in vacuum and it is a longitudinal wave in air.
3. C
   Sound can travel in vacuum and it is a longitudinal wave in air.
4. D
   Sound cannot travel in vacuum and it is a transverse wave in air.

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1. A
   8 m/s
2. B
   12 m/s
3. C
   16 m/s
4. D
   20 m/s

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1. A
   $10 \cdot 0$ m/s
2. B
   $11 \cdot 1$ m/s
3. C
   $11 \cdot 2$ m/s
4. D
   $12 \cdot 1$ m/s

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1. A
   $\text{O}^{2-}$
2. B
   $\text{Na}^+$
3. C
   $\text{Ne}$
4. D
   $\text{N}^-$

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1. A
   3
2. B
   4
3. C
   5
4. D
   6

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1. A
   $\text{CaSO}_4 \cdot \frac{1}{2}\text{H}_2\text{O}$
2. B
   $\text{CaSO}_4 \cdot 2\text{H}_2\text{O}$
3. C
   $\text{CaSO}_4 \cdot 5\text{H}_2\text{O}$
4. D
   $\text{CaSO}_4 \cdot 4\text{H}_2\text{O}$

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1. A
   frequency
2. B
   speed
3. C
   wavelength
4. D
   acceleration

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1. A
   Figure (a)
   
2. B
   Figure (b)
   
3. C
   Figure (c)
   
4. D
   Figure (d)
   

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1. A
   Red light bends the most, as the refractive index of glass for red light is greatest.
2. B
   Red light bends the most, as the refractive index of glass for red light is lowest.
3. C
   Violet light bends the most, as the refractive index of glass for violet light is greatest.
4. D
   Violet light bends the most, as the refractive index of glass for violet light is lowest.

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1. A
   erect, real and larger.
2. B
   erect, virtual and same size.
3. C
   inverted, virtual and same size.
4. D
   inverted, real and smaller.

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1. A
   Frictional force
2. B
   Electric force
3. C
   Gravitational force
4. D
   Spring force

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1. A
   perpendicular to each other.
2. B
   parallel to each other.
3. C
   anti-parallel to each other.
4. D
   equal in magnitude.

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