WAEC Physics questions

379 questions with answers and explanations. Tap an option to check yourself.

1. Question 301· Simple a.c. circuits· WAEC

   Find the reactance of a 0.7 H inductor on a 50 Hz supply. [π = 22/7]

   • A110 Ω
   • B220 Ω
   • C35 Ω
   • D440 Ω

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2. Question 302· Simple a.c. circuits· WAEC

   The frequency of the public electricity supply in Nigeria is

   • A50 Hz
   • B60 Hz
   • C100 Hz
   • D240 Hz

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3. Question 303· Simple a.c. circuits· WAEC

   An alternating current has a peak value of 10√2 A. Its r.m.s. value is

   • A10 A
   • B20 A
   • C14.1 A
   • D5 A

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4. Question 304· Simple a.c. circuits· WAEC

   The peak value of an alternating current is 10√2 A. Find its r.m.s. value.

   • A14.1 A
   • B20 A
   • C10 A
   • D5 A

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5. Question 305· Simple a.c. circuits· WAEC

   The unit of inductive reactance is the

   • Aohm
   • Bhenry
   • Cfarad
   • Dhertz

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6. Question 306· Simple a.c. circuits· WAEC

   In a purely resistive a.c. circuit, the current and voltage are

   • A180° out of phase
   • B90° out of phase
   • Cin phase
   • Dalways zero

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7. Question 307· Simple a.c. circuits· WAEC

   In a purely inductive a.c. circuit, the current

   • Ais always zero
   • Bleads the voltage by 90°
   • Cis in phase with the voltage
   • Dlags the voltage by 90°

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8. Question 308· Simple a.c. circuits· WAEC

   The r.m.s. value of an a.c. voltage with peak 340 V is about

   • A240 V
   • B340 V
   • C480 V
   • D170 V

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9. Question 309· Simple machines· WAEC

   A pulley system of velocity ratio 3 lifts a load of 300 N with an effort of 125 N. Find its efficiency.

   • A2.4%
   • B80%
   • C120%
   • D60%

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10. Question 310· Simple machines· WAEC

    The efficiency of a machine is always less than 100% because

    • Athe effort is small
    • Bthe load is heavy
    • Csome energy is lost to friction
    • Dthe velocity ratio is large

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11. Question 311· Simple machines· WAEC

    An inclined plane is 5 m long and 1 m high. Its velocity ratio is

    • A5
    • B1
    • C0.2
    • D6

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12. Question 312· Simple machines· WAEC

    A machine has a mechanical advantage of 4 and a velocity ratio of 5. Find its efficiency.

    • A125%
    • B80%
    • C20%
    • D9%

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13. Question 313· Simple machines· WAEC

    A screw jack has a pitch of 0.5 cm and its handle turns in a circle of radius 35 cm. Find the velocity ratio. [π = 22/7]

    • A70
    • B220
    • C440
    • D880

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14. Question 314· Simple machines· WAEC

    A pulley system lifts a 600 N load with an effort of 200 N. The mechanical advantage is

    • A800
    • B0.33
    • C3
    • D400

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15. Question 315· Simple machines· WAEC

    In a pulley system the load is supported by 4 strands of rope. What is the velocity ratio?

    • A4
    • B2
    • C8
    • D1/4

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16. Question 316· Simple machines· WAEC

    A pulley system lifts a load of 600 N with an effort of 200 N. Its mechanical advantage is

    • A4
    • B3
    • C0.33
    • D12

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17. Question 317· Simple machines· WAEC

    A machine of velocity ratio 5 lifts a load of 400 N with an effort of 100 N. Find its efficiency.

    • A80%
    • B125%
    • C25%
    • D20%

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18. Question 318· Simple machines· WAEC

    A machine has a velocity ratio of 5 and an efficiency of 80%. Its mechanical advantage is

    • A6.25
    • B4
    • C0.16
    • D400

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19. Question 319· Simple machines· WAEC

    In a first-class lever, the fulcrum is

    • Aoutside the lever
    • Bat one end with the load in the middle
    • Cat one end with the effort in the middle
    • Dbetween the effort and the load

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20. Question 320· Sound waves· WAEC

    Ships measure the depth of the sea using

    • Aa barometer
    • Bradar only
    • Cecho sounding
    • Da hydrometer

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