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**Q1. Which of the following is not a vector quantity?**

**इनमें से कौन एक उक्त रेखा (वेक्टर क्वांटिटी) नहीं है?**

(a) Speed / गति

(b) Velocity / वेग

(c) Torque / टार्क

(d) Displacement / विस्थापन

**Ans.(a)**

Sol. A vector quantity has a direction and a magnitude, while a scalar has only a magnitude, Speed is a scalar quantity.

**Q2. The dimensional formula for universal gravitational constant is**

**सार्वभौमिक गुरुत्वाकर्षण स्थिरता के लिए आयामी सूत्र क्या है?**

(a) [M^(-2)]

(b) [M^(-1) L^3 T^(-2)]

(c) [M^(-1) L^3 T^2]

(d) [ML^2 T^(-2) ]

**Show Answer**

**Ans.(b)**

Sol. According to the newton’s law of gravitation, the force of attraction between two objects of mass m_1 and m_2 can be given as F=(Gm_1 m_2)/r^2 , where G is the gravitational constant and r is the distance between the objects

∴G=(F×r²)/(m_1×m_2 ), now on putting the dimensional formula of F, r, m_1 and m_2 in the given expression, we can get the dimensional formula for G as

([F]×[r]²)/([m_1 ][m_2])=([MLT^2 ]×[L]²)/([M][M])

=[M^(-1 ) L^3 T^(-2)]

**Q3. Decibel is used to measure the intensity of**

**डेसिबल का उपयोग किस की तीव्रता को मापने के लिए किया जाता है?**

(a) Magnetic field/ चुंबकीय क्षेत्र

(b) Sound/ ध्वनि

(c) Light/ प्रकाश

(d) Heat/ऊष्मा

**Show Answer**

**Ans.(b)**

Sol. The decibel ( dB) is used to measure sound level, but it is also widely used in electronics, signals and communication. The dB is a logarithmic way of dscribing a ratio. The ratio may be power, sound pressure, voltage or intensity or several other things.

**Q4. A micron is equal to**

**एक माइक्रोन किस के बराबर है-**

(a) 0.1 mm

(b) 0.01 mm

(c) 0.001 mm

(d) 0.0001 mm

**Show Answer**

**Ans.(c)**

Sol. 1 Microns is equal to 0.001 Millimeters.

**Q5 Dimensional formula of latent heat**

**गुप्त गर्मी का आयामी सूत्र क्या है?**

(a) M0L2T-2

(b) MLT-2

(c) ML2T-2

(d) ML2T-2

**Show Answer**

**Ans.(a)**

Sol. Latent heat is given by energy per unit mass. The dimensional formula is [M0L2T–2].

**Q6. Therm is the unit of**

**थर्म किस की इकाई है ?**

(a) Power/ शक्ति

(b) Heat/ऊष्मा

(c) Light/प्रकाश

(d) Distance/दूरी

**Show Answer**

**Ans.(b)**

Sol. The Therm (symbol, thm) is a non-SI unit of heat energy equal to100000 British thermal units (Btu). It is approximately the energy equivalent of burning 100 cubic feet (2.83 cubic metres) – often referred to as 1 CCF – of natural gas.

**Q7. Knot is measure of**

**नॉट क्या मापने में इस्तेमाल किया जाता है?**

(a) The speed of ship/जहाज की गति

(b) The curvature of spherical objects/ गोलाकार वस्तुओं का वक्रता

(c) Solar radiation/ सौर विकिरण

(d) Intensity of earthquake shock/ भूकंप की तीव्रता

**Show Answer**

**Ans.(a)**

Sol. A knot is one nautical mile per hour (1 knot = 1.15 miles per hour ). The term knot dates from the 17th century, when sailors measured the speed of their ship by using a device called a “common log.” This device was a coil of rope with uniformly spaced knots, attached to a piece of wood shaped like a slice of pie.

**Q8. The dimension of which of the following is the same as that of impulse?**

**निम्नलिखित में से किस का आयाम आवेग के समान है?**

(a) Volume /आयतन

(b) Momentum / संवेग

(c) Torque /टार्क

(d) Change in the rate of momentum / संवेग की दर में बदलाव

**Show Answer**

**Ans.(b)**

Sol. Dimensional formula for impulse and momentum are same MLT-1.

**Q9. Which among the following is the fundamental quantity?**

**निम्नलिखित में से क्या एक मौलिक मात्रा है?**

(a) Volume /आयतन

(b) Time /समय

(c) Velocity /वेग

(d) Force /बल

**Show Answer**

**Ans.(b)**

Sol. Time in physics is defined by its measurement: time is what a clock reads. In classical, non-relativistic physics it is a scalar quantity and, like length, mass, and charge, is usually described as a fundamental quantity.

**Q10. The dimensional formula of coefficient of viscosity is**

**श्यानता के गुणांक का आयामी सूत्र क्या है?**

(a) [MLT-1]

(b) [M-1L2T-2]

(c) [ML-1T-1]

(d) None of these/ इनमें से कोई नहीं

**Show Answer**

**Ans.(c)**

Sol. Coefficient of viscosity is defined as tangential force required to maintain a unit velocity gradient between two parallel layers of liquid of unit area. Mathematically, Coefficient of viscosity (η)= Fr/Av ( where F= tangential Force, Area, r= distance between the layers, v= velocity.

viscosity (η)= (MLT-2 x L )/ (L2 x LT-1)

= (ML2T-2)/L3T-1

= ML-1T-1.

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