the ray which causes gas molecules to glow is known as

• A. cathode ray
• B. anode ray
• C. molecular ray
• D. gamma ray

A heating coil rated 1000 W is used to boil off completely 2 kg of boiling water. the time required to boil of the water is_______[Special latent heat of Vaporization of water = 2.3 x 10⁶ Jkg^-1]

• A) 1.15 x 10⁴s
• B) 1.15 x 10³s
• C) 4.6 x 10⁴s
• D) 4.6 x 10³s

Which expression gives magnetic flux?

• A. qVB sin\(\theta\)
• B. \(\frac{\mu \phi I}{2 \pi r}\)
• C. BA cos \(\theta\)
• D. -N \(\frac{d \phi}{dt}\)

The average speed of an object is determined by dividing the sum of its initial and final speeds by two only when the acceleration is

• A. changing
• B. uniform
• C. increasing
• D. decreasing

An electric drill rated 400W is used to drill a hole in copper of mass 400g in 20s. Calculate the rise in temperature if all the heat produced is absorbed by the copper. [specific heat capacity of copper = 400Jkg^-1K^-1]

• A. 100^oC
• B. 75^oC
• C. 50^oC
• D. 45^oC

The process through which free electrons leave the surface of hot metal is known as?

• A) photon emission
• B) photo emission
• C) thermionic emission
• D) electron emission

The pitch of a note is not affected by

• A. frequency
• B. tension in a vibrating string
• C. mass of a vibrating string
• D. amplitude of sound wave

A steady current of 2A flows in a coil of emf 12V for 0.4s. A back emf of 3V was induced during this period. The stored energy in the loop that can be utilized is

• A. 9.6J
• B. 2.4J
• C. 12.0J
• D. 7.2J

When a positively charged rod is brought nearer the cap of a positively charged electroscope, the leaves divergence will

• A) be induced
• B) converge
• C) diverge
• D) remain constant

Total internal reflection occurs when light moves from?

• A. a dense medium to a less dense medium
• B. air to water
• C. water to glass
• D. a less dense to a dense medium