GameChanger Academy

Mechanics

1. Units, Dimensions and Errors

2. Vectors and Scalars

3. Motion in a Straight Line

4. Projectile Motion

5. Newton's Laws of Motion

6. Friction

7. Work, Energy, Power and Collision

8. Circular motion

9. Rotational motion

10. Simple Harmonic Motion

11. Gravitation

12. Elasticity

13. Surface Tension

14. Fluid dynamics and Viscosity

15. Hydrostatics

Heat and Thermodynamics

16. Thermometry

17. Thermal expansion

18. Calorimetry, Change of State and Hygrometry

19. Gas Laws and Kinetic theory of Gases

20. Transmission of Heat

21. Thermodynamics

Sound and Waves

22. Wave

23. Superposition of Waves

24. Stationary/ Standing waves

25. Doppler's effect and Musical sound

Optics

26. Reflection of Plane and Curved Mirrors

27. Refraction at Plane surfaces and Total internal reflection

28. Refraction through prism and Dispersion of Light

29. Refraction through Lenses

30. Chromatic abberation in Lenses, Optical instruments and Human eye

31. Velocity of Light

32. Photometry

33. Wave nature of Light

Electrostatics

34. Charge and Force

35. Electric Field and Potential

36. Capacitance

Electrodynamics

37. Electric current

38. Heating Effect of Current

39. Thermoelectricity

40. Chemical effect of Current

41. Meters

Electromagnetism

42. Properties of Magnets

43. Magnetic effects of Current

44. Electromagnetic induction

45. Alternating current

Modern Physics

46. Cathode rays, Positive rays and Electrons

47. Photoelectric effect

48. X-rays

49. Atomic structure and Spectrum

50. Radioactivity

51. Nuclear physics

52. Semiconductor and Semiconductor devices

53. Diode and Triode valves

54. Logic gates

55. Relativity and Universe

56. Particle physics

Electrodynamics

38. Heating Effect of Current

1. If the power consumed through a 10 kΩ resistance is 1 W, then current is:

[BP 2013]

1 A
0.01 A
0.001 A
0.0001 A

2. A bulb rated 100 W; 200 V was supplied with 160 V line. What was power dissipated?

[BP 2012]

64 W
75 W
52 W
85 W

3. A heater coil is cut into two equal parts and only one part is used in the heater. How will the heat generated vary?

[BP 2011]

Becomes one fourth
Halved
Doubled
Becomes four times

4. Two electric bulbs A and B are connected in parallel to a constant voltage source. A and B are rated as 60 Watt and P Watt respectively. If the resistance of A and B are in the ratio 2:3, P will be

[MOE 2014]

20 Watt
25 Watt
30 Watt
40 Watt

5. Heater is 1000 W then, energy consumed in 2 hrs is

[IOM 2012]

2 J
20 kJ
2 kWh
200 W

6. 25 W - 220 V and 100 W - 220 V is joined in series with 220 V mains then power will be

[IOM 2012]

4 W and 16 W
32 W and 16 W
8 W and 32 W
16 W and 64 W

7. A bulb is rated at 100 V, 220 W, when the voltage drops by 2%, then change in power of bulb is:

[KU 2014]

Increased by 2%
Increase by 4%
Decreases by 2%
Decreases by 4%

8. If the strength of current increases by 1% then the power of the bulb will change by

[KU 2014]

9. If the power of a heater is 1 W, 1 A ampere of current is passed through it. Then find the resistance

[KU 2010]

4.25 Ω
4200 Ω
1 Ω
0.1 Ω

10. Two electric bulbs have tungsten filaments of same length. If one of them gives 60W and other gives 100W

[IE 2010]

60 W filament is thicker than 100 W filament
100 W filament is thicker than 60 W filament
Both same
Thickness does not determine the wattage of wire

11. The power and voltage of a bulb is 100 W and 220 V. When the voltage is made 110 V, the power would be

[IE 2012]

50 watt
100 watt
75 watt
25 watt

12. The two bulbs at same voltage have power 200 watt and 100 watt respectively. Find out the ratio of their resistance

[IE 2013]

R₁ = R₂
R₁ = 2R₂
R₂ = 2R₁
R₁ = 4R₂

13. Fuse wire should have

[KU 2009]

High resistivity, low melting point
High resistivity and high melting point
Low resistivity, high melting point
Low resistivity and low melting point

14. Two identical electric bulbs 200 W, 250 V are connected in parallel across 250 V. Power consumed by the combination is

[MOE 2011]

400 W
100 W
1600 W
1200 W

15. A bulb is rated as 60 watt and 120 volt. The current through the bulb when the bulb is lighted at the rated voltage is

[Bangladesh Emb]

0.5 A
5 A
25 A
0.25 A

16. If the strength of the current is decreased by 4%, the power of the bulb will change by

[MOE 2000]

8%
0.01%
2%
nearly 4%

17. A bulb with 220 volt consumes the power of 66 watt. If it will be connected with 160 volt then the power consumed by the bulb will be

[IOM 1999]

10 W
40 W
60 W
35 W

18. The power of two heater coils is P₁ & P₂. If they are connected in series, the resultant power is

[IOM 2002]

P₁ + P₂
P₁P₂/(P₁ + P₂)
√(P₁P₂)
(P₁ + P₂)/P₁P₂

19. The power of a bulb is 100 watt at 220 V. When the voltage is 110 V, power of the bulb is:

[IOM 2001]

150 W
50 W
120 W
25 W

20. If two bulbs whose resistances are in the ratio 1:2 are connected in series. Then their powers will be in the ratio

[IE 2004]

21. Calculate energy dissipated when 0.3A of current is passed at 6V in 2 minutes

[IE 2006]

206 J
216 J
318 J
122 J

22. Two resistances 10Ω and 20Ω are connected in parallel. If P is the power consumed by 10Ω, then power consumed by 20Ω is

[MOE 2008]

23. Two resistance of 10Ω & 20Ω joined in series. The power in 10Ω resistor is P then what is the power in 20Ω

[IE 2007]

24. A resistor operated at 100V generates joule heat at a rate of 20W. When placed across a 50V source, it will draw:

[IE 2007]

0.1A
5A
20A
4A

25. Three identical bulbs are arranged in parallel across 220V supply and the current across each is 40A. The total energy consumed in 1hr is

[BPKIHS 2001]

8.8 kWh
16.6 kWh
26.4 kWh
80 kWh

26. Power dissipated by R₁ and R₂ resistor are 100 watt and 200 watt respectively when connected to same voltage. Their relation between R₁ and R₂ is

[BPKIHS 2002]

R₁ = R₂
R₁ = R₂/2
R₁ = 2R₂
R₂ = 3R₁

27. Two heater wires of equal length are first connected in series and then in parallel, the ratio of heat production in the two cases is

[BPKIHS 2004]

28. Two wires of the same mass and material are drawn 1 mm and 2 mm thick. They are connected in series and a current is sent through them. The heat produced will be in the ratio

[MOE Curriculum]

1:16
16:1
1:4
2:1

29. In order to light a 6W - 6V bulb at rated power a battery of emf 6V and internal resistance 2Ω is used. The bulb will light at power:

[IOM 2005]

6W
27/8W
4W
16/3W

30. Five equal resistors when connected in series dissipated 5 watt power. If they are connected in parallel, the power dissipated will be

[MOE 2009]

25 W
50 W
100 W
125 W

31. If R₁ and R₂ are respectively resistances of a 200W bulb and a 100W bulb, designed to operate on the same voltage, then

[BPKIHS 2007]

R₁ = 2R₂
R₂ = 2R₁
R₂ = 4R₁
R₁ = 4R₂

32. In the current in an electric bulb drops by 2% the power decreases by

[KU 2012]

33. Two bulb 25W, 220V and 100W, 220V are connected in parallel across 220V mains. The current is more through

[IOM 2010]

25W bulb
100W bulb
same in both bulbs
I is fluctuating

34. A 25W, 220V bulb and a 100W, 220V bulb are joined in series and connected to the mains. Which bulb will grow brighter?

[BPKIHS 2009]

25W bulb
100W bulb
first 25W bulb then 100W bulb
both will glow with same brightness

35. A 25W, 220V bulb and a 100W, 220V bulbs are joined in parallel and connected to the 220V mains. Which bulb will glow more brightly?

[MOE 2011]

25W bulb
100W bulb
both will glow with the same brightness
none

36. Two resistances R and 2R are connected in series in an electrical circuit. The ratio of heat in 2R to that in R is:

[KU 2013]

37. Two bulbs 100W, 250V and 200W, 250V are connected in series across a 500V line. Then:

[BPKIHS]

100W bulb will be fused
200W bulb will be fused
both bulb will be fused
no bulb will be fused

38. A uniform wire when connected directly across a 200V-line produces heat H per sec. If the wire is divided into n parts and all parts are connected in parallel across a 200V-line. The heat per second will be

[IOM 2008]

H
nH
n²H
H/n

39. Two electric bulbs rated P₁ watt, V volt and P₂ watt V-volt are connected in parallel across V-volt supply. The total power consumed is:

[MOE 2012]

P₁ + P₂
V(P₁ + P₂)
√(P₁P₂)
(P₁ + P₂)/V

40. Two head lamps of a car are in parallel. They together consume 48W with the help of a 6V battery. The resistance of each bulb is:

[BPKIHS 2006]

2/3Ω
3Ω
4Ω
1.5Ω

41. A fuse wire with a radius 1mm blows at 1.5A. If the fuse wire of the same material should blow at 3.0A, the radius of the must be:

[IOM 2007]

4^1/3 mm
2 mm
0.5 mm
8.0 mm

42. Two bulb of 25W, 200W has resistances in the ratio:

[BPKIHS 2010]

43. A 500 watt heating unit is designed to operate from a 115 volt-line. If the voltage drops to 110 volt, the percentage drop in the heat output will be:

[MOE 2013]

10.2%
8.1%
8.6%
7.6%

44. A bulb rated 220V, 100W is connected across 160V line. The power dissipated will be

[IOM 2014]

100W
75W
52W
26W

45. Two electric bulbs, each designed to operate with a power of 500 watts and 220 volts line are connected in series in 110 volts line. The power generated by each bulb will be:

[BPKIHS 2012]

31.25 watts
40 watts
60 watts
3.125 watts

46. A heating coil is labeled 100W, 220V. The coil is cut into two equal parts and two pieces are joined in parallel to the same source. The energy now liberated per second is

[IOM 2009]

25 J
50 J
200 J
400 J

47. The electric bulbs have tungsten filaments of same length. If one of them gives 60 watts and the other 100 watts, then

[MOE 2010]

100 watts bulb has thicker filament
60 watts bulb has thicker filament
both filaments are of same thickness
insufficient information

48. A cell of emf E and internal resistance r supplies currents for same time through external resistance R₁ and R₂ separately. If the heat developed in the external resistance in the two cases is same, r is

[IOM 2006]

(R₁ + R₂)/2
R₁ - R₂
√(R₁R₂)
1/R₁R₂

49. An electric kettle has two coils. When one of these is switched on, the water in the kettle boils in 6 minutes. When the other coil is switched on, the water boils is 3 minutes. If the two coils are connected in series, the time taken to boil the water in the kettle is

[BPKIHS 2005]

2 minutes
3 minutes
6 minutes
9 minutes

50. In an ordinary heater if the length of the coil is halved, then a given quantity of water will boil in

[MOE 2007]

less time
more time
same time
can not be compared

51. Five electric bulbs each of 40 watt burns 5 hours each day. Calculate the cost in the month of 30 days; if the cost of 1 unit is Rs. 8

[IOM 2008]

Rs. 320
Rs. 240
Rs. 160
Rs. 420

52. In a room one bulb of 1000W burns 5 hour each day. In the same room a heater of 100W burns 4 hour each day. Calculate total energy consumption in 30 days

[MOE 2009]

162 units
125 units
145 units
155 units

53. An electric heater rated as 500 W, 220V raises the temperature of 1kg of water at 15°C to the temperature of boiling point in 15 minutes. Calculate the heat efficiency of the heater

[BPKIHS 2003]

162%
65%
79%
87%

54. The same mass of copper is drawn into two wires of thickness 1mm and 2mm. If two wires are connected in series and current is passed, then heat produced in the wires is in the ratio of

[IOM 2004]

16:1
9:4
1:16
4:9

55. A bulb is rated as 6V, 6W is connected through a supply of 6V and 1Ω internal resistance. Find the power consumption of bulb

[BPKIHS 2008]

210 W
116 W
25 W
222 W

56. A bulb is rated as 100W, 220V and 200W, 220V are connected in series through a supply of 220V. Find the total power consumption

[MOE 2015]

44.4W
22.2W
12.4W
66.6W

57. The voltage across an electric bulb is increased by 50%. Find the percentage change in power

[KU 2016]

100%
125%
200%
300%

58. How much energy is dissipated as heat during a two minute time interval by a 1.5kΩ resistor which has a constant 20V potential difference across its leads?

[KU 2015]

53 J
46 J
32 J
72 J