Subject :NSO Class : Class 7
A scientist took a metal rod and a wooden rod and wrapped each of them in a piece
of paper. These were then heated as shown. It was found that the paper around the
metal rod does not burn whereas the one around the wooden rod catches fire. It is because
Ans 1:
Class : Class 7
option A
Ans 2:
Class : Class 7
i think it is "A".
Ans 3:
Class : Class 7
Ans 4:
Class : Class 7
The answer should be A because iron is a good conductor of heat it will take away all the heat given to paper and the paper will not burn.
But in case 2 , we see that there is a wooden rod we all know that wood is a good insulator of heat so it will catch fire easily and the paper wrapped on it will burn easily.
In the experiment below, when the flask
was placed in hot water, the level of the drop of
ink dropped and then rose because the __________ expanded first, followed by the expansion
of _______.
The speed of a train increases at a constant rate
a from zero to v, and then remains constant for an interval, and finally decreases to zero at a constant rate
b. If L be the total distance travelled, then the total time taken is
A particle is moving in a straight line with initial velocity
u and uniform acceleration f. If the sum of the distances travelled in
tth and (t +
1)th seconds is 100 cm, then its
velocity after t seconds in cm/s is
Which square must be shaded so that the
figure has a line of symmetry ?
A particle of mass 0.3 kg is subjected to a force
F = kx with k = 15 N/m and
x being its distance from the origin. What will be its initial acceleration if it is released from
a point 20 cm away from the origin ?
In desert plants, leaves modify into thorns. How do thorns help a plant?