A few grains of table salt were put in a cup of cold water, kept at constant temperature and left undistributed. Eventually all the water tested salty. This action is due to?
Which of the following statements about radioactivity is true?
(i) Alpha particle is positively charged
(ii) Beta particle is negatively charged
(iii) Gamma ray is neutral
(iv) Beta particle has the same mass as helium atom
(v) Gamma ray is charged.
A. i, ii, iii, iv only
B. i, ii, iii only
C. iv and v only
D. i, ii and v only
Natural radioactivity consists of emission___
A. α-particles and β-rays
B. α-particles and X-rays
C. γ-ray and X-rays
α-particles and β-rays and γ-rays
A transformer has 300 turns of wire in the primary coil and 30 turns in the secondary coil. If the input voltage is 100 volts, the input voltage is
A. 5 volts
B. 10 volts
C. 15 volts
D. 20 volts
Two mirrors of the same length are arranges as show in the diagram. A ray of light NO strikes the system at O and emerges along PQ. The emergent ray has been deviated through
A ship travelling towards a cliff receives the echo of its whistle receives the echo of its whistle after 3.5 seconds. If the speed of sound in air under the prevailing conditions is 250ms−1, how much closer is the ship to the cliff?
Heat is supplied uniformly at the rate of 100W to 1.0 x 10−2kg of a liquid for 20 seconds. If the temperature of the liquid rises by 5oC , then the specific heat capacity of the liquid is
A. 2.0 x 102Jkg-1K-1
B. 2.0 x 102Jkg-1
C. 4.0 x 104Jkg-1K-1
D. 4.0 x 104Jkg-1
Which of the following instruments consumes the highest current?
I. Electric iron
II. Television set
III. Torch light
IV. Immersion heater