# Model Questions Of Science For Diploma & Bridge Course

### Entrance Preparation practice set-I

1. Each side of a cube is 2 mm. Then, volume of this cube will be...........

Given, Each side of cube(l)= 2 mm
Volume of cube(V)=?
We know that,
V = l³
= (2 mm)³
= 8 mm³
= 8×10⁻⁹ m³ (∵1 mm³ = 10⁻⁹ m³)

2. Amount of heat energy required to raise the temperature of 100 gram of water from 20°C to 30°C is equal to..........

Mass of water (m)= 100 g = 0.1 kg
Change in temperature (dt) = 30°C - 20°C = 10°C
Amount of heat (Q) = ?
According to the formula,
Q = m × s × dt
= 0.1 × 4200 × 10
(∵s = 4200 J/Kg°C being specific heat capacity of water)

= 4200 Joule(J) proved.

3. The wavelength of a wave of frequency 50 Hz and velocity 4×10⁴ cm/sec is equal to........

Given, Velocity (V) = 4×10⁴ cm/s
Frequency(f) = 50 Hz
Wavelength() = ?
We know that,
V = f × λ
or, λ = f/V
= (4 ×10⁴)/50
= 40000/50
= 800 cm

4. Fermi is unit of........

Fermi is the unit of distance which is named after the great scientist Enrico Fermi.

5. 1 kWh of energy is equal to.........

Given, Power(P) = 1 kilowatt(kW) = 1000 Joule/sec
( ∵1 kW = 1000 W and 1 W = 1 Joule/sec)

Given time(t) = 1 hour = 3600 sec
Hence, the total energy consumed in 1 hour (W) = P×t
=1000×3600
=3600000
=3.6×10 Joule.

6. Equivalent resistance of 5 ohm, 10 ohm and 15 ohm connected in parallel is..........

1ˢᵗ Resistance(R₁) = 5 ohm(Ω)
2ⁿᵈ Resistance(R₂) = 10 ohm(Ω)
3ʳᵈ Resistance(R₃) = 15 ohm(Ω)
Equivalent Resistance (R) = ?
We know that,
1/R = (1/R) + (1/R) + (1/R)
or, 1/R =1/5 + 1/10 + 1/15
or, 1/R = (6+3+2)/30
or, 1/R = 11/30
or, 11R = 30
or, R = 30/11
∴ R = 2.72 ohm (Ω)

7. A convex mirror of focal length 10 cm makes a virtual image of an object placed at a distance of 5 cm from the mirror. Then the image distance will be equal to.......

Explanation:
Given, In a convex mirror,
focal length (f) = 10 cm
object distance (u) = 5 cm
image distance (v) = ?
We know that,
(1/u) + (1/v) = 1/f
or, (1/5) + (1/v) = 1/10
or, (v + 5)/5v = 1/10
or, 10(v + 5) = 5v
or, 10v + 50 = 5v
or, 10v - 5v = -50
or, 5v = -50
or, v = -50/5
or, v = - 10 cm
Since, distance is always positive,
∴image distance (v) = 10 cm

8. Length contraction and time dilation are the consequences of .................

Length contraction and time dilation are the consequences of special theory of relativity (the theory which shows the time travel being possible).

9. The kinetic energy of a particle of mass 5 gram and linear momentum equal to 2 Ns is.................

Explanation:
Given, For the particle,
mass (m) = 5 g = 0.005 kg
linear momentum (P) = 2 Newton second (Ns)
Kinetic energy (KE),= ?
We know that,
KE = mv²/2

Multiplying numerator and denominator by m, we get
KE = (mv²× m)/2m
or, KE = (mv)²/2m
or, KE = (P)²/2m
[∵Linear momentum (P)= mass(m)× velocity(v)]

or, KE = 2²/ 2×0.005
or, KE = 4/0.01
or, KE = 400 Joule .

10. Electric charge...............

Electric charge can have only discrete values because it cannot be produced nor destroyed but can be changed from one form to another form or state.

11. Current can be passed through an electrolyte due to movement of

Current can be passed through an electrolyte due to the movement of ions.

12. An electric bulb is rated as 60 watt & 220 volt. Its resistance will be equal to

For the electric bulb,
Voltage(V) = 220 volt
Power (P) = 60 watt
Resistance (R) = ?
We know that,
R = V²/P =(220)²/60 = 48400/60 = 806.6 ohm.

13. The melting point of solid with increase in preasure:

For metals in equilibrium condition, their volume expands during melting.
Applying pressure on these materials suppress the volumetric expansion and delays the melting. As a result, the melting temperature increases if you apply pressure.
But the inverse happens for water. Melting of ice is associated with volume contraction during transfirmation and thus the temperature decreases with pressure.

14. A particle starts moving with a velocity of 4 m/s & uniform acceleration of 2 m/s² and it travels half of its journey in the last second of its motion. Time taken to complete the journey is

Initial Velocity (u) = 4 m/s
Uniform Acceleration (a) = 2 m/s²
Final Velocity (v) 2 m/s [∵ Acceleration is uniform that means 2 m/s in every second]
Time (t) = ?
We know that,
a = (v-u)/t
or, 2 = (2-u)/t
or, 2t = -2
∴t = -1
Since, time is always positive, t= 1 second.
Now, time taken to complete half journey = 1 second
time taken to complete full journey = 2 sees.

15. A pendulum clock is when taken to the top of mountain it

When the pendulum clock is taken to the top of mountain, the value of 'g' will decrease and hence time period will increase. As the pendulum takes more time to complete one vibration, it will lose time.

16. Diopter is S.I. unit of

Diopter is S.I. unit of power of lens.

17. The mirror convenient for shaving purpose is

The concave mirror is convenient for shaving purpose because when the face is held within the focus of concave mirror then an enlarged image of the face is seen in the concave mirror

18. The amount of heat required to change 20 gram ice at 0⁰C into water at 0⁰C into water at 40⁰C will be equal to

Mass of ice (m) = 20g = 0.02kg
change of temperature (dt) = 40⁰C - 0⁰C = 40⁰C
Amount of heat (Q) =?
We know that,
Q= m×s×dt
= 0.02kg × 4200J/Kg⁰C × 40⁰C[∵ The specific heat capacity of water(s) = 4200 J/kg⁰C
3360J
Again we have,
4.2J = 1 calorie
or, 1J = 1/4.2 calorie
3360J = 1/4.2 × 3360 calorie = 800 calorie.

19. If 2 minutes is the time taken to carry a bucket of water of mass 5 kg to a height of 10 meter, then electrical power consumed will be

Given, Mass(m) = 5kg
Distance (s) = 10m
Time(t) = 2 min = 120 secs.
Electric Power(P) = ?
We know that,
1kg = 10 Newton
5kg = 10×5 N = 50N
∴ force (f) = 50N
Again, we know that,
work done (w) = F×S =50×10 =500 Joule
Again, we know that,
Power (p) = W/T = 500/120 = 4.16 watt.

20. If the earth stops rotating about its own axis, then...
where gₚ and gₑ are acceleration due to gravity at the pole and equator respectively.

The value of acceleration due to gravity(g) is maximum at poles and minimum at the equator because the centrifugal force for the earth's spinning is vanishes at poles and maximum at the equator. If the earth suddenly stops rotating about its axis, there is no effect of centrifugal force on the gravitational acceleration. So, the value of gravitational will be same at all places.

21. The elements A,B,C,D and E have atomic number 2,3,7,10 and 18 respectively. The elements which belong to the same period of periodic table are

Li, N, Ne belongs to the same period of periodic table.

22. Bronze is an alloy of

Cu+Zn+Sn.

23. In LPG the smell is due to

LPG gas is basically the mixture of propane and butane. Due to sulphur, it smells like pungent, rotten eggs. Ethanethiol is intentionally added to butane and propane to impart an easily noticed smell to these normally odorless fuels that pose the threat of fire, explosion, and asphyxiation.

24. An element X forms two oxides XO and XO₂. The oxide XO is neutral but XO₂ is acidic in nature. The element X is most likely to be

CO₂ on reaction with water form carbonic acid. So it is acidic in nature. while CO is neutral as it do not react with acid or base to form salt and water.

25. Epsom salt is

MgSO₄.

26. Which isotope of hydrogen has no any neutron?

Protium.

27. The compound which contains both ionic and covalent bond is

CH₄

28. Consider a liquid A having Pᴴ>7. A drop of another liquid B is added to it. On addition of liquid B colour of solution changes from colourless to pink. what may be liquid A and B.

KOH, phenolphthalein.

29. The dry ice is

Solid CO₂.

30. The general formula of alkene is

CₙH₂ₙ.

31. When a current is passed through an electrolyte containing ions then

All ions move to oppositely charged plate.

32. Heavy water is

Heavy water is the water containing deuterium instead of normal hydrogen (protium) used as a moderator in nuclear reactor.

33. Sodium is kept in

Because sodium is highly reactive metal and it easily and quickly reacts with water and atmospheric air. Therefore, it is kept in kerosene.
Similarly, Phosphorus is also very reactive that's why it is kept in water to prevent it from undergoing reaction with air .

34. Which is the correct electronic configuration of oxide ion?

The correct electronic configuration of oxide ion is 1s²2s²2p⁴.

35. Which of the following has largest radius?

36. Which one of the following animal is mammal ?

Platypus.

37. Which one of the following is example of reflex action?

Heart beat.

38. Polio is caused by

virus.

39. Bacteriophage is ... :

Virus.

40. Which one is not the base pair of DNA ?

Uracil is not the base pair of DNA.

41. Mening is external protective membrane of :

Mening is external protective membrane of brain and spinal cord.

42. Dry scales and cold blodded animals are found in

Dry scales and cold blodded animals are found in reptilia.

43. Which one is dihybrid phenotypic ratio of Mendal's experiment:

In first case,
Let round seed plant = RR
wrinkled seed plant = rr

Crossbreeding both plants we will get first filial or f1 generation as follows:-
RR×rr = {Rr,Rr}
Thus in F1 generation only dominant character is seen. so, both offsprings is seem to be hybrid round seed plants.

Again crossbreeding the offsprings we will get F2 generation as follows:-

Crossbreeding F₁ generation's offsprings
× R r
R RR Rr
r Rr rr

Thus, in F2 generation both dominant and recessive character is seen. so, 25% offsprings is pure round seed plants, 50% is hybrid round seed plants and 25% is pure wrinkled seed plants. That means 3 plants are round seed plants and 1 plants is wrinkled seed plants.
∴ Phenotypic ratio is 3:1.
In 2nd case,
Let yellow seed plants = YY
green seed plants = yy
Then, doing the same as process as above we will get F2 generation as follows:-

Crossbreeding F₁ generation's offsprings
× Y y
Y YY Yy
y Yy yy

Now, crossbreeding the offsprings of F2 generation of round and wrinkled seed plants with that of yellow and green seed plants we will get

Crossbreeding F2 generations' offsprings of both case
× RR Rr Rr rr
YY RRYY RrYY RrYY rrYY
Yy RRYy RrYy RrYy rrYy
Yy RRYy RrYy RrYy rrYy
yy RRyy Rryy Rryy rryy

As you can see above in the table, 9 offsprings {RRYY, RrYY, RrYY, RRYy, RrYy, RrYy, RRYy, RrYy, RrYy} shows both dominant (R) and dominant (Y) character that means 9 plants are round yellow seed plants.
Whereas, 3 offsprings {RRyy, Rryy, Rryy} shows dominant (R) but recessive (y) character that means 3 plants are round green seed plants.
In the other hand, 3 offsprings {rrYY, rrYy, rrYy} shows recessive (r) but dominant (y) character. so 3 plants are wrinkled yellow seed plants.
At last, only one offsprings (rryy) shows both recessive (r) and recessive (y) character. so it is wrinkled green seed plant.
∴ Dihybrid phenotypic ratio of Mendel's experiment is 9:3:3:1.

44. Binary fission is the method of reproduction in

Binary fission is the method of reproduction in paramecium.

45. Which one of following is not producer ?

Prawn is not a producer.

46. Fern plant belongs from the group

Fern plant belongs from the group pteridophyta which lacks seeds and reproduce by shedding spores by the process of sporulation.

47. Which one is true fish

Dog fish.

48. Thyroxine hormone is secreted from

Thyroxine hormone is secreted from thyroid gland.

49. Cell plate formation takes place in