भौतिक विज्ञान (Physics) – Physics MCQ
भौतिक विज्ञान (Physics) – CEE प्रवेश
Physics · Medical Entrance (CEE) – Physics, Chemistry, Biology & MAT · ४०७ प्रश्न
४०७ प्रश्न उपलब्ध। मोड छान्नुहोस्:
भौतिक विज्ञान (Physics): प्रश्न र उत्तर
सही लागेको विकल्पमा थिच्नुहोस्। सही भए हरियो, गलत भए रातो देखिन्छ; ३ सेकेन्डपछि सही उत्तर र व्याख्या देखिन्छ।
सही: ० / ०
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Two resistors of 10 Ω and 20 Ω are connected in series with a battery of 12 V. What is the potential drop across the 20 Ω resistor?
सही उत्तर: घ) 10 V
When resistors are connected in series, the current through both resistors is the same. Using Ohm's law (V = IR), we can calculate the potential drop across each resistor. For the 20 Ω resistor, V = I * 20Ω. The total resistance is 10Ω + 20Ω = 30Ω and current, I = V/R = 12V/30Ω = 0.4A. Therefore, potential drop across 20Ω resistor = 0.4A * 20Ω = 8V. Options A, B and C are incorrect calculations.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A wire carrying a current I is placed in a uniform magnetic field B perpendicular to its surface. If the length of the wire is L and the force on it is F, what is the value of B?
सही उत्तर: क) F / (L*I)
The force on a current-carrying wire in a magnetic field is given by F = ILBsinθ, where θ is the angle between the wire and the magnetic field. Setting θ=90°, we get F = ILB. Therefore, B = F/(LI). Options 1 and 2 are incorrect because they don't use the correct formula. Option 3 involves division by L which should be in denominator and Option 4 contains a sign error
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The refractive index of glass is 1.5 for light travelling parallel to its surface. What is the angle of minimum deviation?
सही उत्तर: ग) 60°
The formula for the angle of minimum deviation (δ) is δ = A sin(θ/2), where A is the refractive index and θ is the angle of incidence. At minimum deviation, the bent ray passes through the principle focus of the lens. Thus, δ= 45° is correct. Options 30°, 60°, and 90° are incorrect because they don't satisfy the conditions for minimum deviation.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A light bulb emits light at an average wavelength of 400 nm. What is the energy of a single photon emitted by the bulb? (h=6.626 x 10⁻³⁴ Js, c=3 x 10⁸ m/s)
सही उत्तर: क) 3.98 x 10⁻¹⁹ J
We can use the equation E = hc/λ, where E is energy, h is Planck's constant, c is the speed of light, and λ is the wavelength. Plugging in the values: E = (6.626 x 10⁻³⁴ Js * 3 x 10⁸ m/s) / 400 x 10⁻⁹ m = 3.98 x 10⁻¹⁹ J.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A uniform rod of length 1 meter is placed symmetrically on a frictionless horizontal surface. The rod has a mass of 2 kg. What is the magnitude of the frictional force exerted by the surface on the rod?
सही उत्तर: ग) 3 N
Since the rod is uniform, its center of mass is at its midpoint. The net force acting on the system will cause it to rotate about this point. To prevent rotation (equilibrium), a frictional force must be applied in the opposite direction to the torque created by the weight of the rod. The torque due to gravity is 0.5 kg * 9.8 m/s² = 4.9 N·m. The friction force needed to balance this torque is therefore 4.9 N.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A metal rod of length L and cross-sectional area A is heated through a temperature difference ΔT. The rise in thermal energy (heat) absorbed by the rod is given by:
सही उत्तर: ख) ΔT * L * A
The heat gained (Q) is calculated using the formula Q = mcΔT, where m is mass, c is specific heat capacity, and ΔT is the temperature change. However, we're given length and area. The energy absorbed is proportional to the product of ΔT, A, and L because heat transfer through conduction depends on these factors.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A stone of mass 0.5 kg is thrown upwards with an initial velocity of 10 m/s. Taking g = 9.8 m/s², calculate the maximum height reached by the stone (approximate value).
सही उत्तर: ख) 30.6 m
We can use kinematic equations to solve this. At max height, v = 0. Using v² = u² + 2as (where v=0, u=10m/s, a=-9.8m/s², and s is the displacement), we find s = (10)² / (2 * -9.8) = 30.6 meters.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A particle moves along a straight line with accelerating force F. At time t=0, its velocity is zero and displacement is zero. Which of the following statements about the particle’s motion is correct?
सही उत्तर: ख) The particle's velocity remains constant at zero
Newton’s Second Law states F = ma. Since F is constant and the mass ‘m’ is constant, the acceleration ‘a’ must also be constant to maintain a uniform acceleration. The other options are incorrect as they don't reflect this fundamental principle.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A charged particle enters a uniform magnetic field with a velocity of 5 m/s perpendicular to the field, where the magnetic field strength is 0.2 Tesla. What is the magnitude of the force acting on the charged particle? (Assume the charge of the particle is 1.6 x 10⁻¹⁹ C)
सही उत्तर: क) 8 × 10⁻² N
The force on a charged particle moving in a magnetic field is given by F = qvBsin(θ), where q is the charge, v is the velocity, B is the magnetic field strength, and θ is the angle between the velocity and the magnetic field. In this case, the velocity is perpendicular to the field, so θ = 90°, sin(90°) = 1. The magnitude of the force is qvB.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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In the year 2023, a radioactive material has a mass of 100 g with a half-life of 10 years. What was the initial mass (in grams) of the material at the beginning of 2023?
सही उत्तर: ग) 200
The half-life is the time it takes for half of the material to decay. From the beginning of 2023, 10 years have passed, so there are two half-lives. Therefore the remaining mass is 100g/2^2 = 100g/4=25g This option is wrong and others are more complex.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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