An ebonite rod rubbed with fur attracts a glass rod rubbed with silk because
ebonite has a negative charge while glass has a positive charge
ebonite has a positive charge while glass has a negative charge
both have negative charges
both have positive charges
Correct answer is A
No explanation has been provided for this answer.
1.8 x 10-10N
9.0 x 10-8N
9.0 x 102N
4.5 x 103N
Correct answer is C
F =\(\frac{1}{4{\pi}{\varepsilon}_o}\) x \(\frac {q_1q_2}{r^2}\)
F =\(\frac {5 {\times} 10 {\times} 8 {\times} 10}{0.002 {\times} 0.002}\) x 9 x 10
F = 900N
i, ii, iii and iv
i, ii, iv only
i, iii, iv only
ii, iii, iv only
Correct answer is B
No explanation has been provided for this answer.
14cm
28cm
75cm
150cm
Correct answer is A
F = \(\frac{uv}{u - v}\)
F = +ve
v = -ve
30 = \(\frac {25 {\times} (-v)}{25 - (-v)}\)
v = \(\frac {25 {\times} (-v)}{25+v}\)
v = 14cm
(Note that either negative or positive values go to show the positioning and hence, they are not a strong necessity in your final answer.)
t – n
t (1 + 1/n)
t (1-1/n)
t (1/n - 1)
Correct answer is C
n = \(\frac {\text{real depth}}{\text {apparent depth}{}}\)
n = \(\frac {t}{t-d}\)
\(\frac{t - d}{1}\) = \(\frac{t}{n}\)
-d = \(\frac{t}{n}\) - t
d = - \(\frac{t}{n}\) + t
d = t - \(\frac{t}{n}\)
d =t (1 - \(\frac{1}{n}\))