भौतिक विज्ञान – Physics MCQ
भौतिक विज्ञान – कृषि/वन प्रवेश
Physics · Agriculture, Veterinary & Forestry Entrance · ४२५ प्रश्न
४२५ प्रश्न उपलब्ध। मोड छान्नुहोस्:
भौतिक विज्ञान: प्रश्न र उत्तर
सही लागेको विकल्पमा थिच्नुहोस्। सही भए हरियो, गलत भए रातो देखिन्छ; ३ सेकेन्डपछि सही उत्तर र व्याख्या देखिन्छ।
सही: ० / ०
-
A body of mass 5 kg is pushed horizontally across a surface with a force of 10 N for 2 seconds. What is the magnitude of the acceleration of the body?
सही उत्तर: घ) 10.0 m/s²
Using Newton's second law, Force (F) = mass (m) * acceleration (a). We are given F = 10 N and m = 5 kg. Solving for a gives a = F / m = 10 N / 5 kg = 2 m/s². The other options miscalculate the acceleration by either using incorrect force or mass values.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The speed of sound in air is approximately 340 m/s. If the time interval between seeing a lightning flash and hearing its thunder is 15 seconds, what is the approximate distance from the observer to the point where the lightning struck? (Round off your answer to the nearest kilometer)
सही उत्तर: ख) 840 km
The time taken for sound to travel a given distance is calculated as distance = speed x time. Here, time is 15 seconds and the speed of sound is 340 m/s. Therefore, distance = 340 * 15 = 5100 meters or 5.1 km. The most tempting answer (680km) is clearly incorrect as it’s far from the calculated value. 840km and 1200km are also significantly off.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
A block of mass 2 kg is pushed up an inclined plane with a length of 1 meter and height of 0.5 meters, taking 4 seconds to reach the top. What is the work done against gravity?
सही उत्तर: क) 8.9 J
The work done against gravity (W) can be calculated as W = mgh, where m is mass (2 kg), g is acceleration due to gravity (9.8 m/s²), and h is height (0.5 m). Therefore, W = 2kg * 9.8m/s² * 0.5m = 9.8 Joules. Option 10J is the most misleading as it might be associated with frictional force instead of gravitational pull.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The refractive index of glass with respect to air is 1.5. What is the apparent depth of a swimming pool if its actual depth is 10 meters?
सही उत्तर: क) 5m
Apparent depth is given by the formula: Apparent Depth = Actual Depth * (Refractive Index - 1). Therefore, Apparent Depth = 10m * (1.5 - 1) = 10m * 0.5 = 5m. The other options are incorrect calculations applying the refractive index incorrectly or misunderstanding its role in optical phenomena.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
A wave travels at a speed of 300 m/s and has a wavelength of 2 meters. What is the frequency of the wave?
सही उत्तर: क) 10 Hz
The relationship between wave speed (v), wavelength (λ) and frequency (f) is v = fλ. Therefore, f = v/λ = 300 m/s / 2m = 150 Hz. The incorrect answers represent either misapplication of the formula or a misunderstanding of the units.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Two identical lenses, each having a power of +1D, are placed facing each other. What is the focal length of the combination?
सही उत्तर: क) -1 D
The combined power of two lenses is the sum of their individual powers. In this case, the combined power is +2D. The focal length (f) of a lens with power P is given by 1/f = |P|. Therefore, f = 1/|+2D| = 1/2 D = 0.5 D. The most tempting incorrect option is -1D as it relates to the negative sign but doesn't reflect the correct calculation based on combined power.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The resistance of a wire increases when its temperature rises. Explain this phenomenon.
सही उत्तर: ख) Due to the increased atomic vibrations
As temperature increases, the atoms within the wire vibrate more vigorously. These vibrations impede the flow of electric current, leading to an increase in resistance. Options B, C and D are incorrect explanations.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
If a body moves with uniform acceleration, its velocity at any given time is...
सही उत्तर: ख) Proportional to time
According to Newton's second law (F = ma) and the definition of acceleration (a = Δv/Δt), if acceleration is constant, velocity changes linearly with time. Options B, C, and D present incorrect relationships between velocity and time for non-uniform motion.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
A body falls vertically downwards from a height of 20 meters. What will be its velocity just before hitting the ground (take g = 10 m/s²)?
सही उत्तर: ख) 10√3 m/s
Using the equation of motion: v² = u² + 2as, where u is initial velocity (0), a is acceleration (g=10 m/s²) and s is displacement (20m). Therefore, v² = 20*20 = 400, so v = √400 = 20 m/s. Options B and C use incorrect calculations; D calculates the time instead of velocity.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The potential difference across a conductor increases when the resistance decreases. Explain this phenomenon briefly.
सही उत्तर: ख) Due to the increase in current flow
This statement reflects Ohm's Law (V = IR), where voltage is directly proportional to resistance. An increase in resistance leads to a decrease in current, and vice-versa. Options B, C and D describe alternative mechanisms that don’t relate potential difference to resistance directly.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
यी अभ्यास प्रश्न हुन्, आधिकारिक प्रश्न होइनन्। पाठ्यक्रम, विज्ञापन र नतिजाका लागि सम्बन्धित निकायको आधिकारिक वेबसाइट हेर्नुहोस्। उत्तरमा गल्ती भेटे प्रश्नमुनिको "टिप्पणी / गल्ती रिपोर्ट" मा लेख्नुहोस्।
नमस्ते! पाठ्यक्रम, सामान्य ज्ञान, भाषा परीक्षा वा कुनै प्रश्नको उत्तर बुझ्न सोध्नुहोस्।
AI ले गल्ती गर्न सक्छ। महत्वपूर्ण कुरा आधिकारिक स्रोतमा जाँच्नुहोस्।