SPSC PHYSICS 25 YEARS PAST PAPERS
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چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
جنریٹر میں استعمال ہونے والے برش عام طور پر _____ سے بنا ہوتے ہیں؟
- Copper
- Steel
- Carbon
- None of these
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Explanation
Carbon brushes are used in generators because they provide good conductivity, low friction, and self-lubrication, reducing wear on the commutator.Unlike copper or steel, carbon is soft and does not damage the rotating parts.
ایک انڈکٹر کنڈلی _____ کی طرح ظاہر ہوسکتا ہے؟
- Solenoid
- LED
- Toroid
- None of these
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Explanation
An inductor coil is typically wound in a helical shape, similar to a solenoid, to generate a magnetic field when current passes through it.Solenoids and inductors both store magnetic energy and follow the same principles of electromagnetic induction.
مندرجہ ذیل میں سے کون سے کسی کو ایوومیٹر سے ماپا نہیں جاسکتا؟
- Inductance
- Voltage
- Resistance
- None of these
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Explanation
An Avometer (Ammeter-Voltmeter-Ohmmeter) can measure voltage (V), current (A), and resistance (Ω) but not inductance (L).Inductance is measured using an LCR meter or an inductance bridge, not a standard Avometer.
مقناطیسی فیلڈ چلتی کنڈلی گالوانومیٹر میں استعمال _____ ہوتا ہے؟
- Longitudinal
- Transverse
- Radial
- None of these
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Explanation
A moving coil galvanometer uses a radial magnetic field to ensure that the coil experiences torque in a uniform manner, regardless of its position.This field is achieved using a curved permanent magnet.This allowing the plane of the coil to always be perpendicular to the magnetic field.
اس کے محور کے ساتھ سولینائڈ کے اندر مقناطیسی فیلڈ _______؟
- Infinite line
- Non-uniform
- Strong and uniform
- None of these
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Explanation
Inside a solenoid, the magnetic field is strong and uniform along its axis.Due to the superposition of magnetic fields from multiple coils.This field is given by B = μ₀nI, where n is the number of turns per unit length and I is the current.
زیادہ تر الیکٹرانک آلات میں استعمال ہونے والے مزاحم ______ سے بنے ہیں؟
- Rubber
- Gold
- Carbon
- None of these
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Explanation
Carbon resistors are commonly used in electronic circuits because they are cheap, stable, and provide precise resistance values.Other materials like metal film or wire-wound resistors are used for specialized applications, but carbon remains the most widely used.
الیکٹرک سرکٹ کی وجہ سے حرارتی اثر ______ کے طور پر لکھا جاتا ہے؟
- H=IR^2t
- H=I^2R
- H=I^2Rt
- None of these
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Explanation
The Joule’s Law of Heating states that heat produced in a conductor is given by H = I²Rt, where I is current, R is resistance, and t is time.This formula explains the conversion of electrical energy into heat in resistors, like in electric heaters and filament bulbs.
الیکٹران کی بہاؤ کی رفتار ______ ہے؟
- 10^-3 m/sec
- 10^-8 m/sec
- 3 × 10^-8 m/sec
- None of these
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Explanation
Drift velocity is the average velocity of electrons due to an applied electric field in a conductor.It is typically very small, in the range of 10⁻⁴ to 10⁻³ m/s, because electrons undergo frequent collisions while moving through the conductor.
ایک پوائنٹ چارج سے لامحدود فاصلے پر بجلی کی شدت ______ ہوگی؟
- Zero
- Infinite
- Positive
- None of these
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Explanation
Electric intensity (electric field) due to a point charge is given by:
E= kq/r^2
As the distance r → ∞ (infinite), the value of 1/r^2 becomes zero.
Therefore, the electric intensity at infinite distance becomes zero.
Last updated 14-feb-2026
کسی بھی شے پر کم سے کم چارج ______ سے کم نہیں ہوسکتا؟
- 1.8 × 10⁻¹⁶ e
- 1.3 × 10⁻¹⁴ e
- 1 × 10⁻¹⁹ e
- None of these
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Explanation
The minimum possible charge on any object is the charge of a single electron or proton, which is 1.6 × 10⁻¹⁹ C.But in terms of elementary charge (e), it is written as 1 × 10⁻¹⁹ e.No object can have a charge smaller than this because charge is quantized in multiples of e.
